Synthesis and Characterization of Bifunctional Organic-Glasses Based on Diphenylhydrazone and Barbituric Acid Derivative for Photorefractive Application

Abstract

A series of amorphous molecules that possess both photoconductive and electro-optic properties was synthesized in order to investigate photorefractive properties of bifunctional organic-glasses. Diethylaminobenzaldehyde-diphenylhydrazone was covalently attached to 5-(4-diethylamino-benzylidene)-1,3-dimethylpyrimidine-2,4,6-trione through a flexible alkyl chain (3, 4, 5, 6 and 10 carbons) containing two ether linkages. The longer linkage not only lowered the glass transition temperature (<TEX>$T_g$</TEX>) of the molecules, but also allowed faster orientation of the chromophore. To examine the photorefractive properties, a 50 <TEX>${\mu}$</TEX>m-thick film was prepared from the mixture of a bifunctional molecule, butyl benzyl phthalate, and <TEX>$C_{60}$</TEX>. The photoconductivity of this composite was as high as <TEX>$8.01\;{\times}\;10^{-12}$</TEX> S/cm at 60 V/ <TEX>${\mu}$</TEX>m, and the maximum diffraction efficiency ( <TEX>${\eta}_{max}$</TEX>) of 50 <TEX>${\mu}$</TEX>m-thick film was about 5% at 80 V/ <TEX>${\mu}$</TEX>m.