Preparation of Highly Efficient Polymeric Photorefractive Composite Containing an Isophorone-Based NLO Chromophore

We synthesized 2-{3-[( E )-2-(dibutylamino)-1-ethenyl]-5,5-dimethyl-2-cyclohexenylidene}malononitrile as a noval nonlinear optical (NLO) chromophore for photorefractive materials. The photorefractive polymeric composite composed of photoconducting carbazole-substituted polysiloxane, NLO chromophore, and 2,4,7-trinitro-9-fluorenone exhibited excellent photorefractive properties. The gain coefficient of the composite containing 30 wt % of chromophore was as high as 390 cm -1 at the electric field of 100 V/μm, which is one of the largest values obtained so far in the field of polymeric photorefractive materials. And the composite with a thickness of 60 μm showed the maximum diffraction efficiency of 56% at 30 V/μm.