Soluble high-Tg polymers containing disperse red chromophore that display nonlinear optical activity

We have synthesized NLO polymers containing azobenzene moieties connected by imide linkages or urethane linkages. The intensity of the second harmonic generation (SHG) signal from spin-cast films of these polymers were 2 to 14 times higher than that from Y-cut quartz. The highest SHG intensity was obtained in PU-DR19 because of the flexible urethane linkages (14 times that from Y-cut quartz). PI-1-DR19 also showed a high SHG (10 times that from Y-cut quartz), but a smaller one than that in PU-DR19. Among the polymers synthesized in this work, the polymers containing urethane linkages showed higher-intensity second harmonic signals than did those possessing imide linkages because of the former's higher flexibility. The values of T-g of the polymers were in the range 140 similar to 158 degrees C; the 10% weight loss temperatures appeared in the range 290 similar to 320 degrees C. PU-S-DR19 showed a higher value of T-g than did DU-DR19 because of its spiroacetal moiety. All of these polymers were readily soluble in common organic solvents, such as chloroform, NMP, and DMF.