Design and Synthesis of Thermally Stable Chromophores with Low

Chapter 7

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Design and Synthesis of Thermally Stable Chromophores with Low Absorption at Device Operating Wavelengths Susan Ermer, Steven M. Lovejoy, and Doris S. Leung Lockheed Martin Palo Alto Research Laboratory, Research and Development Division, Organization 93-50, Building 204, 3251 Hanover Street, Palo Alto, CA 94304-1191 A series of novel, lambda-shaped chromophores combining thermal stability above 375 °C, transparency at 830 nm, and nonlinearity/MW comparable to Disperse Red 1 have been developed. These "DAD-type" chromophores are based on the dicyanomethylenepyran acceptor group and can be viewed as donor-acceptor-donor analogs of DCM, a chromophore that has already been used for demonstration devices. Thermal stability within a polyimide environment has been demonstrated using one of the chromophores, DADC, in a fully-cured polyimide waveguide device patterned by photobleaching. Functionalization for improved solubility has been demonstrated, and a readily attachable variant has been generated. The detailed syntheses and full chemical characterization of these chromophores are described. Since the introduction of polyimide-based electro-optic (EO) materials in 1991, much progress has been made in their development (1-3). Our goal has been the development of a polymeric based materials system which could be generated in sufficient quantity for device prototyping. Requirements for such a system include ease of preparation, moderate electro-optic activity, transparency, and accessibility to large reproducible lots. Based on these needs, we developed a materials formulation based on commercially accessible components. These components were DCM (4-(dicyanomethylene)-2-memyl-6^(p-dimem^ a polar compound used as a laser dye, and a fluorinated polyimide, Amoco Ultradel. The Ultradel polyimides were developed for use as interlevel dielectric coatings and have been optimized for low ionic content, low dielectric constant, low moisture absorption, and high thermal stability. The main structural component of these materials is shown in Figure 1.

O Jn Figure 1. Main structural component of Amoco Ultradel 4212 and 3112 polyimide 0097-6156/95/0601-0095$12.00/0 © 1995 American Chemical Society Lindsay and Singer; Polymers for Second-Order Nonlinear Optics ACS Symposium Series; American Chemical Society: Washington, DC, 1995.


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POLYMERS FOR SECOND-ORDER NONLINEAR OPTICS

These polymers are highly fluorinated. Fluorination of polymers used in optical fibers has been shown to effect properties such as dielectric constant, refractive index, water absorption and optical loss (4). Absorption losses in a variety of polymers such as polymethylmethacrylate, polycarbonate, and polysulfone, used for polymer optical fibers have been determined to result largely from higher harmonics of molecular vibrations of functional groups, particularly those of C-H, N-H, and O-H (J). Fluorine substituted for hydrogen in these groups shifts these absorptions, reducing optical losses in the critical waveguiding regions of the spectrum (0.8 to 1.6 microns). This explanation may be extended to the fluorinated polyimides. It is also likely that the bulky trifluoromethyl ( - C F 3 ) groups separate the chromophoric centers and inhibit electronic inter-chain interactions. In 1992, we described a proof-of-principle all-polyimide triple stack MachZehnder (M-Z) modulator using these components as the active core layer (6). A crosssectional view of the switching arm of this waveguide is shown in Figure 2. Recently, the same DCM/polyirnide core layer was combined with an acrylate cladding for a high speed device demonstration (7). Efforts are now needed to optimize poling in allpolyimide devices, in order to maximize poling alignment and thereby improve switching sensitivity (5). Studies of ionic content on electrical conduction in certain polyimide single films have been performed (9-/0), but further work is required to fully elucidate the contribution of ionics in three layer stacks during poling. •Electrode (17 mm Long) •H

20/im

}^

1

0

0

0

A

A

u

/

1

S

0

A

c

r

2.5 um Ultradel 4212 Oadding 1.6 /jmDCM/3112 Polyimide U_ 2.5 m Ultradel 4212 Oadding \*+- 1 im Aluminium Ground Plane Waveguide Channel I (5 pm wide x 2 pm thick)

Figure 2. Diagram of DCM/Polyimide Mach-Zehnder Modulator The guest and host components used for Mach-Zehnder prototyping were chosen for their compatibility with processing and device demonstration requirements. High thermal stability is the key advantage offered by the polyimide host materials. They are especially promising for optical interconnection devices which must be processed under the extreme conditions used for semiconductor fabrication (77). Advantages of DCM as guest include low absorbance at device wavelengths, photobleachability, compatibility with polyimides and their polyamic acid precursors, and commercial availability in high purity. Some of these characteristics are the result of DCM's use as a laser dye, which are designed to have sharp cut-offs on the high wavelength side of their major absorption peak, so as to avoid reabsorbing emitted light. The absorption spectrum for DCM shown in Figure 3 peaks at 480 nm in N-methylpyrrolidinone (NMP), and its optimum lasing wavelength is 661 nm. A sharp cut-off wavelength is necessary to avoid absorbance of the laser output, and this same sharp cut-off avoids excess optical loss in devices operating at 830 nm. It can be seen, also, from data presented later in this paper, that DCM offers relatively high nonlinearity for its molecular weight and transparency. DCM is, however, less than optimum in its thermal characteristics. It plasticizes the host material and, when heated above 220 °C for significant periods oftime,outdiffuses. Curing polyimides at temperatures below 220 °C compromises the superior thermal and mechanical properties that prompted their selection as host materials. This out-diffusion has been successfully controlled by physically confining the DCM using an evaporated metal layer over the waveguide, allowing cure at temperatures of up to

Lindsay and Singer; Polymers for Second-Order Nonlinear Optics ACS Symposium Series; American Chemical Society: Washington, DC, 1995.

7.

ERMER ET AL.

Thermally Stable Chromophores with Low Absorption


350 °C (72), but an inherently thermally-stable chromophore would be preferred Plasticization remains a concern, since depression of the glass transition temperature, , of the polyimide host is detrimental to long-term stability of the poled state (13lS). This concern motivated us to develop a series of chromophores which maintain the advantageous properties of DCM while improving its thermal stability. Due to our interest in 830 nm device operation, it was essential to avoid loss of transparency of the new chromophores in this region.

Wavelength (nm) Figure 3. Absorption spectrum of DCM in NMP and its chemical structure (inset) Design and Preparation of Thermally Stable Chromophores Recently, several groups have published the structures of chromophores with thermal stability exceeding 300 °C. Aryl substitution on amine donors has been demonstrated to raise the thermal stability of a wide range of conventional chromophores (16). New chromophore classes have also been developed. Some examples are shown in Figure 4. The triarylimidazole and triaryloxazole classes of compounds have been utilized as EO chromophores by workers at IBM (17) and Sandia (18). While these two chromophores exhibit high thermal stability, their nonlinearities (fj values) have been disappointing. The other two compounds shown exhibit hyperpolarizabilities comparable to standard chromophores such as DR1, but with greatly increased thermal stability. The chromophore SY177 is based on a fused-ring system which is structurally related to polyimide (19). It has been heated to 350 °C in a polyimide without any change in its linear absorption spectrum. Structurally related to DCM, DADC is a donor-acceptor-donor compound based on a dicyanomethylenepyran acceptor attached to two carbazole donors (20). The synthesis and properties of these donor-acceptor-donor analogs of DCM are the focus of this paper. Poled polymers containing these chromophores may be less susceptible to loss of EO activity due to loss of orientation as a result of their "lambda" shape (21). These chromophores exhibit good thermal stability at temperatures over 300 °C and maintain desirable properties such as high hyperpolarizability, transparency at device operation wavelengths, and photobleachabiUty. The high-temperature stability and photo-bleachability of DADC has allowed the use of high processing temperatures in the fabrication of a demonstration Mach-Zehnder modulator (22). New thermally stable chromophores are continually being developed. Based on the progress seen in recent years, it is anticipated that


97

98



thermal stability of chromophobes will not be a significant limitation in the development of manufacturable EO materials. We have found the guest-host approach to be the most practical means of rapid chromophobe development, screening, and investigation in device configuration. Once a chromophore with optimized properties for a given device application is developed, covalent attachment will be a logical next step for enhancement of loading level and long-term stability of the poled state.

CHJCHJ

(c)

CHJCHJ

(d)

Figure 4. Examples of some NLO chromophores stable to >300 °C: (a) triarylimidazole, (b) triaryloxazole, (c) SY177, (d) DADC Synthesis of Donor-Acceptor-Donor Analogs of DCM. The donor-acceptordonor analog of DCM, (2,^bis(2-(4-(dimethylamino)phenyl)-ethenyl)-4//-pyran-4yhdene)propanedinitrile (DAD), has been previously investigated as an impurity arising from the synthesis of DCM (23). The DAD chemical structure may be viewed as containing two cross-conjugated DCM chromophores. This similarity in chromophores of the two compounds leads to UV-visible spectra which are very similar in appearance with nearly coincident absorption maxima. Hie dicyanomethylene [=C(CN)2l group is a highly effective electron acceptor which has been used by a number of groups to synthesize highly active chromophores. It is mostly used as part of dicyanovinyl [CH=C(CN) ] and tricyanovinyl [-C(CN)=C(CN) ] moieties (24-26). Substituted di cyanovinyl [-CR=C(CN)2] moieties have also been used in cyclic acceptors derived from the condensation of isophorone and malononitrile (27-29). We began work on compounds based on the dicyanomethylenepyran moiety shortly after our first studies using DCM. This acceptor group is attractive because it allows the attachment of two different donors in a symmetrical arrangement using Knoevenagel condensation chemistry. This technique provides access to a wide range of DAD-type compounds. Recently, alternate methods of mcorporation of the dicyanomethylenepyran moiety into syndioregic polymers have been described (30). The synthetic scheme for the DAD-type analogs of DCM is shown in Figure 5. In general, the analogs were prepared by refluxing the appropriate aldehyde and (2,6chmemyl-4//-pyran-4-yhdene)pro^ together overnight in benzene or toluene using piperidine and glacial acetic acid as catalysts while removing the generated water with a Dean-Stark trap. After cooling the reaction solution, the precipitated crude analog was filtered and recrystallized (or flash chromatographed then recrystallized) to give the pure analogs. In the cases where no precipitate formed upon cooling, the reaction ?

2


7.

ERMER ET AL.


99


solvent was roto-evaporated to give the solid crude analogs then further purified. The detailed synthetic methods for the preparation of these compounds are given in the Experimental Section.

Figure 5. General scheme of the synthesis of donor-acceptor-donor type analogs Table I shows the donor-acceptor-donor analogs prepared and some of their physical properties. The visible absorption spectra were measured in Nmethylpyrrolidinone (NMP), and the extinction coefficients (e) times 1(H are in parentheses. DAD's onset temperature of weight loss in air was measured in 100% O2. Thermal Stability. The materials in this series exhibit high thermal stabilities both in an inert atmosphere and in the presence of oxygen. We use thermogravimetric analysis (TGA) for rapid screening of the thermal stability of the neat chromophores. A sample of the compound is heated at a steady rate as weight loss is monitored. Weight loss in these compounds may occur due to either decomposition of the compound, or to an evaporative process, such as sublimation. The thermograms for a series of donoracceptor-donor type compounds run under nitrogen atmosphere and in the presence of oxygen are shown in Figures 6 and 7, respectively. In general, the decomposition onset values (see Table I) reported by die Perkin-Elmer TGA-7 using derivative curves are generally higher than temperatures the molecules can withstand during the cure process. We believe this is due to several factors: (1) unmelted compounds are often stabilized by crystal lattice forces, (2) the host environment during cure is often highly reactive, and (3) the chromophore must withstand the higher temperature for a longer time period. This effect is exemplified by DADT, which has TGA decomposition onset temperatures of 331 °C and 343 °C in nitrogen and air, respectively. A DADT/polyimide film was monitored during cure on a hot plate to see if the dissolved chromophore would withstand these temperatures. The film showed color loss indicative of chromophore decomposition at temperatures near 250 °C. Differential Scanning Calorimetry (DSC) run on a sample of DADT showed decomposition immediately upon melting (Moylan, C.R., IBM, personal communication, 1994). Because thermal analysis, whether by TGA or DSC, is performed on a crystalline sample, the decomposition weight loss onset temperature reported may not be predictive of the decomposition onset of a chromophore when it is solubilized within a polymer film. In summary, TGA and DSC are useful screening techniques when looking for stability trends, but do not necessarily accurately predict stability in a host environment Activity. Electric field-induced second harmonic (EFISH) generation experiments at 1.907 microns in chloroform on DAD, DADB, DADI, and DADC were performed by Lap-Tak Cheng (du Pont) and have been reported previously (31). These values are summarized in Table n , together with reference values for Disperse Red 1 (DR1) and DCM run in the same laboratory. The values for Po were calculated using the standard two-level model approximation. The units for both P and Po are 10" esu. The \i and P values for DADI are imprecise due to the insolubility of DADI in the EFISH solvent and are shown in parentheses. 30



100

Table I Donor-acceptor-donor type analog physical properties

Acronym

mp(°0

Onset Onset temperature temperature JtmaxCnm) of weight of weight loss in air loss in N 2

R=

(°Q

C O

N(CH3)2


-0*

DAD

262.7263

491 (6.83)

330

392

DADC

337-338

459(7.15)

375

389

DADB

249.6250.4

500(6.63)

371

387

DADI

315-325

465(6.27)

374

392

DADQH

222.5224.5 Ac

499(7.05)

363

372

529(6.33)

331

1 ^ CH2CH3

—{~)-N(C,H,k

^0 N" CH 3

/ = \

,CH CH OH z

2

H j - ^ r R \ST

CH CH 2

3

300 °C; *H NMR (DMSO-cfc) 8 3.88 (s, 6H, two NCH3), 6.91 (s, 2H, pyran ring CH), 7.19 and 7.97 (two d, / = 16 Hz, 2H each, trans double bond CH), 7.99 (s, 1H, indoleringCH), 7.22-8.28 (m, 8H, aromatic H); FT-IR (KBr) 2202 and 2187 cm- (CN stretch); UV-vis X (NMP) 465 nm (e = 6.27 X 10 ); Anal. Calcd for C30H22N4O: C, 79.28; H, 4.88; N, 12.33. Found: C, 79.38; H, 4.75; N, 12.30. 1

4

max


7.

ERMER ET AL.


Q.6-Bis(2-(4-(ethvl(2-hvd^^ panedinitrile (DADQHY A solution of 4-(ethyl(2-hydroxyethyl)amino)benzaldehyde (3.43 g, 17.8 mmol), (2,6-dimethyl-4//-pyran-4-yUdene)pn)panedinitrile (1.53 g, 8.89 mmol), piperidine (2 mL), and glacial acetic acid (1 mL) in toluene (100 mL) was refluxed overnight using a Dean-Stark trap. The reaction solution was cooled to RT, and the solvent was roto-evaporated. Flash chromatography (9/1 dichloromethane/ethyl acetate) and recrystallizationfromtoluene gave the product as a dark brown powder, 0.75 g (16%): mp 222.5-224.5 °C; H NMR (CDC1 ) 8 1.20 (t, / = 6.8 Hz, 6H, two l

3


N C H 2 C H 3 ) , 1.74 (t, / = 5.5 Hz, 2H, two OH), 3.49 (q, / = 6.8 Hz, 4H, two NCH2CH3), 3.54 (t, / = 5.9 Hz, 4H, two NCH2CH2OH), 3.83 (dt, / = 5.5 and 5.9

Hz, 4H, two NCH2CH2OH), 6.43 and 7.41 (two d, / = 15.5 Hz, 2H each, trans

double bond CH), 6.49 (s, 2H, two cyclohexene ring CH), 6.74 and 7.41 (two d, / = 8.7 Hz, 4H each, aromatic H); FT-IR (KBr) 2204 and 2189 cm" (CN stretch); UV-vis *max (NMP) 499 nm (e = 7.05 X 10*); Anal. Calcd for C32H34N4O3: C, 73.54; H, 6.56; N, 10.72. Found: C, 73.08; H, 6.42; N, 10.54. 1

(2.6-Bis(2-(5-(l-pvrolidinvn^ (DADTV A solution of 5-(l-pyrrolidinyl)-2-thiophenecarboxaldehyde (1.45 g, 8.00 mmol), (2,6-dimethyl-4//-pyran-4-ylidene)propanedinitrile (0.69 g, 4.00 mmol), piperidine (2 mL), and glacial acetic acid (1 mL) in benzene (100 mL) was refluxed overnight under argon using a Dean-Stark trap. Thereactionmixture was cooled to RT and filtered. The crude product was washed with benzene, thenrecrystallizedfrom N,N-dimethylformamide to give die product as brown crystals, 1.14 g (57%): mp >350 °C; FT-IR (KBr) 2180 and 2196 cm' (CN stretch); UV-vis X*nax (NMP) 603 nm (e = 4.75 X 10 ), 529 nm (e = 6.33 X 10 ), 432 nm (e = 2.46 X 10 ); Anal. Calcd for C28H26N4OS2: C, 67.44; H, 5.26; N, 11.24; S, 12.86. Found: C, 67.34; H, 5.38; N, 11.42; S, 12.62. 1

4

4

4

(2.6-Bis(2-(9-hexvl-9//^aihazo^^^ (DADCHV A solution of 9-hexyl-3-carbazolecarboxaldehyde (3.76 g, 13.4 mmol), (2,6Kiimethyl-4//-pyran-4-yUdene)propanedinitrile (1.15 g, 6.7 mmol), and piperidine (2 mL) in toluene (25 mL) was refluxed overnight using a Dean-Stark trap. The reaction solution was cooled to RT, and the precipitated crude solid was filtered and recrystallizedfromtoluene to give the product as dark orange crystals, 1.63 g (35%): mp 226.4-226.9 °C; *H NMR (CDCI3) 8 0.88 (t, / = 6.5 Hz, 6H, two CH3), 1.23-

1.46 (m, 12H, aliphatic CH ), 1.82-1.94 (m, 4H, aliphatic CH ), 4.31 (t, / = 7.2 Hz, 4H, two NCH2), 6.49 (s, 2H, two pyran ring CH), 6.69 and 7.67 (two d, / = 16 Hz, 2H each, four trans double bond CH), 7.28-8.28 (m, 14H, aromatic H); FT-IR (KBr) 2206 cm" (CN stretch); UV-vis X (NMP) 460 nm (e = 6.98 X 10 ); Anal. Calcd for C48H46N4: C, 82.97; H, 6.67; N, 8.06. Found: C, 82.58; H, 6.52; N, 8.29. 2

2

1

4

max

(2.6-Bis(2-(l-hexvlmdol-3^ A solution of l-hexyl-3-indolecarboxaldehyde (0.80 g, 3.47 mmol), (2,6-dimethyl-4//pyran-4-ylidene)propanedinitrile (0.30 g, 1.74 mmol), and piperidine (1 mL) in toluene (25 mL) wasrefluxedfor 5 hours using a Dean-Stark trap. Thereactionsolution was cooled to RT, roto-evaporated,redissolvedin dichloromethane, passed through a short bed of silica, and roto-evaporated again. Theresultingsolid wasrecrystallizedfrom toluene to give the product as aredcrystalline solid, 0.64 g (62%): mp 194.3-195 °C; U NMR (CDCI3) 8 0.91 (t, / = 6 Hz, 6H, two CH3), 1.26-1.44 (m, 12H, aliphatic CH ), 1.85-1.98 (m, 4H, two NCH2CH2), 4.20 (t, / = 7 Hz, 4H, two NCH ), 6.57 (s, 2H, two cyclohexene ring CH), 6.72 (d, / = 16 Hz, 2H, two trans double bond CH), 7.30-7.47 (m, 6H, aromatic H), 7.52 (s, 2H, two indole ring C2 H), 7.76 (d, / = 16 Hz, 2H, two trans double bond CH), 7.98 (dd, / = 6.3 and 2 Hz, 2H, aromatic H); FT-IR (KBr) 2203 cnr (CN stretch); UV-vis X (NMP) 466 nm (e = 6.22 X l

2

2

1

max


107

108


4

10 ); Anal. Calcd for C40H42N4O: C, 80.78; H, 7.11; N , 9.42. Found: C, 80.47; H, 6.90; N , 9.25.


Acknowledgments Portions of this work have been funded by Lockheed Independent Research and Development and by John Zetts of Air Force Wright Laboratory (WL/MLPO), whose support and interest in this technology is greatly appreciated. We thank S. Maider and S. Gilmour (both of QT/JPL) for advicerelatedto the preparation of the thiophenecontaining donor aldehyde, M.M. Steiner and J. Zegarski of the Lockheed Chemistry Department for thermal analyses and FT-IR characterization of die materials, and L.-T. Cheng (du Pont) for EFISH measurements. Finally, we acknowledge members of the Lockheed Photonics group, including D.G. Girton, W. Anderson, T.E. Van Eck, and J. Marley, for continuing discussion and guidance which have been invaluable to the development of chromophores compatible with device requirements. Literature Cited 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11.

12.

13. 14. 15. 16.

Wu, J.W.; Valley, J.F.; Ermer, S.; Binkley, E.S.; Kenney, J.T.; Lipscomb, G.F.; Lytel, R. Appl. Phys. Lett. 1991, 58, 225-227. Wu, J.W.; Binkley, E.S.; Kenney, J.T.; Lytel, R.; Garito, A.F. J. Appl. Phys. 1991, 69, 7366-7368. Ermer, S.; Kenney, J.T.; Wu, J.W.; Valley, J.F.; Lytel, R.; Garito, A.F. ACS Polymer Preprints 1991, 32(3), 92-93. Matsuura, T.; Hasuda, Y . ; Nishi, S.; Yamamoto, F. Macromolecules 1991, 24, 5001-5005. Takezawa, Y . ; Taketani, N . ; Tanno, S.; Ohara, S. J. Polym. Sci., Part B: Polym. Phys. 1992, 30, 879-885. Ermer, S.; Valley, J.F.; Lytel, R.; Lipscomb, G.F.; Van Eck, T.E.; Girton, D.G. Appl. Phys. Lett. 1992, 61(19), 2272-2274. Girton, D.G.; Anderson, W.W.; Valley, J.F.; Van Eck, T.E.; Dries, L.J.; Marley, J.A.; Ermer, S., this volume. Girton, D.G.; Ermer, S.; Valley, J.F.; Van Eck, T.E.; Lovejoy, S.M.; Leung, D.S.; Marley, J. ACS Polymer Preprints 1994, 35(2), 219-220. Neuhaus, H.J.; Day, D.R.; Senturia, S.D. J. Electron. Mat. 1985, 14, 379-404. Smith, F.W.; Neuhaus, H.J.; Senturia, S.D.; Feit, Z.; Day, D.R.; Lewis, T.J. J. Electron. Mat. 1987, 16, 93-106. Lytel, R.; Lipscomb, G.F.; Binkley, E.S.; Kenney, J.T.; Ticknor, A.J. In Materials for Nonlinear Optics: Chemical Perspectives, Marder, S.R., Sohn, J.E., and Stucky, G.D., Eds.; ACS Symposium Series 455; American Chemical Society: Washington, DC, 1991; pp 103-112. Fujimoto, H.H.; Das, S.; Valley, J.F.; Stiller, M.; Dries, L.; Girton, D.; Van Eck, T.; Ermer, S.; Binkley, E.S.; Nurse, J.C.; Kenney, J.T. In Electrical, Optical, and Magnetic Properties of Organic Solid State Materials, Garito, A.F., Jen, A . K . - Y . , Lee, C.Y.-C., and Dalton, L.R., Eds.; Materials Research Society Symposium Proceedings 328; Materials Research Society: Pittsburgh, PA, 1993; pp 553-564. Liu, L . - Y . ; Ramkrishna, D.; Lackritz, H.S. Macromolecules 1994, 27, 59875999. Valley, J.F.; Wu, J.W.; Ermer, S.; Stiller, M.; Binkley, E.S.; Kenney, J.T.; Lipscomb, G.F.; Lytel, R. Appl. Phys. Lett. 1992, 60, 160-162. Stähelin, M.; Burland, D.M.; Ebert, M . ; Miller, R.D.; Smith, B.A.; Twieg, R.J.; Volksen, W.; Walsh, C.A. Appl. Phys. Lett. 1992, 61, 1626-1628. Twieg, R.J.; Burland, D . M . ; Hedrick, J.; Lee, V . Y . ; Miller, R.D.; Moylan, C.R.; Seymour, C.M.; Volksen, W.; Walsh, C.A. In Organic, Metallo-organic, and


7. ERMER ETAL.

17. 18.


19. 20.

21. 22.

23. 24.

25. 26. 27. 28. 29.

30. 31. 32. 33. 34. 35. 36.

37.


109

Polymeric Materials for Nonlinear Optical Applications, Marder, S.R. and Perry, J.W., Eds.; Proc. SPIE 2143; Society of Photo-Optical Instrumentation Engineers: Bellingham, WA, 1994; pp 2-13. Moylan, C.R.; Miller, R.D.; Twieg, R.J.; Betterton, K . M . ; Lee, V.Y.; Matray, T.J.; Nguyen, C. Chem. Mater. 1993, 5, 1499-1508. Cahill, P.A.; Seager, C.H.; Meinhardt, M.B.; Beuhler, A.J.; Wargowski, D.A.; Singer, K.D.; Kowalczyk, T.C.; Kosc, T.Z. In Nonlinear Optical Properties of Organic Materials VI, Möhlmann, G.R., Ed.; Proc. SPIE 2025; Society of PhotoOptical Instrumentation Engineers: Bellingham, WA, 1993; pp 48-55. Shi, R.F.; Wu, M.H.; Yamada, S.; Cai, Y . M . ; Garito, A.F. Appl. Phys. Lett. 1993, 63, 1173-1175. Ermer, S.; Leung, D.; Lovejoy, S.; Valley, J.; Stiller, M . In Organic Thin Films for Photonic Applications Technical Digest, Volume 17; Optical Society of America: Washington, DC, 1993; pp 50-53. Yamamoto, H.; Katogi, S.; Watanabe, T.; Sato, H.; Miyata, S.; Hosomi, T. Appl. Phys. Lett. 1992, 60, 935-937. Girton, D.; Ermer, S.; Valley, J.F.; Van Eck, T.E. In Organic Thin Films for Photonic Applications Technical Digest, Volume 17; Optical Society of America: Washington, D C , 1993; pp 70-72. Hammond, P.R. Optics Comm. 1979, 29(3), 331-333. Katz, H.E.; Dirk, C.W.; Singer, K.D.; Sohn, J.E. In Advances in Nonlinear Polymers and Inorganic Crystals, Liquid Crystals, and Laser Media, Musikant, S., Ed.; Proc. SPIE 824; Society of Photo-Optical Instrumentation Engineers: Bellingham, WA, 1987; pp 86-92. Jen, A.K.-Y.; Rao, V.P.; Wong, K.Y.; Drost, K.J. J. Chem. Soc., Chem. Commun. 1993, 90-92. Rao, V.P.; Jen, A.K.-Y.; Wong, K.Y.; Drost, K.J. J. Chem. Soc., Chem. Commun. 1993, 1118-1120. Lemke, R. Chem. Ber. 1970, 103, 1894-1899. Mignani, G; Soula, G.; Meyrueix, R. Fr. Patent 2 636 441, 1990; Chem. Abstr. 1990, 113, 181123n. Gadret, G; Kajzar, F.; Raimond, P. In Nonlinear Optical Properties of Organic Materials IV, Singer, K.D., Ed.; Proc. SPIE 1560; Society of Photo-Optical Instrumentation Engineers: Bellingham, WA, 1991; pp 226-237. Stenger-Smith, J.D.; Henry, R.A.; Chafin, A.P.; Lindsay, G.A. ACS Polymer Preprints 1994, 35(2), 140-141. Ermer, S.; Girton, D.G.; Leung, D.S.; Lovejoy, S.M.; Valley, J.F.; Van Eck, T.E.; Cheng, L.-T. Nonlinear Optics 1994, in press. Marder, S.R.; Beratan, D.N.; Cheng, L.-T. Science 1991, 252, 103-106. Marder, S.R.; Perry, J.W.; Tiemann, B.G.; Gorman, C.B.; Gilmour, S.; Biddle, S.; Bourhill, G. J. Am. Chem. Soc. 1993, 115, 2524-2526. Dirk, C.W.; Katz, H.E.; Schilling, M.L.; King, L.A. Chem. Mater. 1990, 2, 700-705. Lin, J.T.; Hubbard, M.A.; Marks, T.J.; Lin, W.; Wong, G.K. Chem. Mater. 1992, 4, 1148-1150. Zysset, B.; Ahlheim,. M . ; Stähelin, M . ; Lehr, F.; Prêtre, P.; Kaatz, P.; Günter, P. In Nonlinear Optical Properties of Organic Materials VI, Möhlmann, G.R., Ed.; Proc. SPIE 2025; Society of Photo-Optical Instrumentation Engineers: Bellingham, WA, 1993; pp 70-77. Meyrueix, R.; Tapolsky, G.; Dickens, M . ; Lecomte, J.-P. In Nonlinear Optical Properties of Organic Materials VI, Möhlmann, G.R., Ed.; Proc. SPIE 2025; Society of Photo-Optical Instrumentation Engineers: Bellingham, WA, 1993; pp 117-128.



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38. Becker, M.W.; Sapochak, L.S.; Ghosen, R.; Xu, C.; Dalton, L.R.; Shi, Y.; Steier, W.H.; Jen, A.K.-Y. Chem. Mater. 1994, 6, 104-106. 39. Sotoyama, W.; Tatsuura, S.; Yoshimura, T. Appl. Phys. Lett. 1994, 64, 21972199. 40. Jen, A.K.-Y.; Drost, K.J.; Rao, V.P.; Cai, Y.; L i u , Y.-J.; Mininni, R.M.; Kenney, J.T.; Binkley, E.S.; Marder, S.R.; Dalton, L.R.; Xu, C. ACS Polymer Preprints 1994, 35(2), 130-131. 41. Yu, D.; Yu, L. ACS Polymer Preprints 1994, 35(2), 132-133. 42. Ermer, S.; Valley, J.F.; Lytel, R.; Lipscomb, G.F.; Van Eck, T.E.; Girton, D.G.; Leung, D.S.; Lovejoy, S.M. In Organic and Biological Optoelectronics, Rentzepis, P.M., Ed.; Proc. SPIE 1853; Society of Photo-Optical Instrumentation Engineers: Bellingham, WA, 1993; pp 183-192. 43. Stenger-Smith, J.D.; Fischer, J.W.; Henry, R.A.; Hoover, J.M.; Nadler, M.P.; Nissan, R.A.; Lindsay, G.A.J. Polym. Sci., Part A: Polym. Chem. 1991, 29, 1623-1631. 44. Woods, L.L. J. Am. Chem. Soc. 1958, 80, 1440-1442. 45. Hopfinger, A.; Cislo, J.; Zielinska, E. Rocz. Chem. 1968, 42(5), 823-828; Chem. Abstr. 1969, 70, 3729a. 46. Hartmann, H.; Scheithauer, S. J. Prakt. Chem. 1969, 311, 827-843. RECEIVED January 30, 1995


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