Synthesis and characterization of a new photoconducting poly(siloxane) having pendant diphenylhydrazone for photorefractive applications

Abstract

A new photoconducting polymer, diphenyl hydrazone-substituted polysiloxane, was successfully synthesized by the hydrosilylation method and characterized by FT-IR, H-1-NMR, and Si-29-NMR spectroscopy. The glass transition temperature (T,) of the polysiloxane having pendant diphenyl hydrazone was ca. 62 degreesC, which enabled a component of a low-T-g photorefractive material to be prepared without the addition of any plasticizers. This polysiloxane, with 1 wt% of C-60 dopant, showed a high photoconductivity (2.8 X 10(-12) S/cm at 70 V/mum) at 633 nm, which is necessary for fast build-up of the space-charge field. A photorefractive composite was prepared by adding a nonlinear optical chromophore, 2-{3-[2-(dibutylamino)-1-ethenyl]-5,5-dimethyl-2-cyclohexenylidene} malononitrile. into the photoconducting polysiloxane together with C60. This composite shows a large orientation birefringence, (Deltan = 2.6 X 10(-3) at 50 V/mum) and a high diffraction efficiency of 81% at an electric field of 40 V/mum.