Synthesis of nonlinear optical polymers with large photoconductive sensitivity and transparency

Novel nonlinear optical (NLO) chromophore, 2-{3-2-(4-methylsulfonylphenyl)vinyl]carbazol-9-yl}ethanol was synthesized and subsequently reacted with methacryloyl chloride to give a photoconducting NLO monomer ( M1 ). 2-Methylacrylic acid 2-3-(diphenylhydrazonomethyl)carbazol-9-yl]ethyl ester ( M2 ) was also synthesized as a comonomer to enhance the carrier mobility of the NLO polymer. Photoconducting NLO polymers, P1 and P2 were obtained by the copolymerization of Ml with methyl methacrylate and M2 , respectively. These polymers were well soluble in organic solvents and showed glass transition at 177 °C and 196 °C, respectively. Polymer films of P1 and P2 were optically clear, and were transparent at wavelengths longer than 420 nm. The electro-optic coefficient (r₃₃) of poled P1 films was measured to be ～5 pm/V at 632.8 nm. The photoconductive sensitivities of P1 and P2 were 6.2 × 10^?14 S·cm^?1/mW·cm^?2 and 5.6 × 10^?11 S·cm^?1/mW·cm^?2.