Synthesis and Structural Effect of Multifunctional Photorefractive Polymers Containing Monolithic Chromophores

Multifunctional photorefractive polymers bearing five different monolithic chromophores as pendant units were synthesized. Monolithic chromophores are composed of the electron-donating and photoconducting carbazole and the electron-withdrawing nitro group which are connected directly or via different conjugation bridges of azobenzene, stilbene, benzoxazole, and cyanostilbene moiety. Acrylate derivatives of these chromophores were copolymerized with butyl acrylate to give photorefractive polymers with T g near room temperature. The structural effects of these monolithic photorefractive chromophores were investigated in terms of the optical nonlinearity, photoconductivity, and photorefractivity of the acrylate copolymers. The opposite direction of asymmetric energy transfer in two-beam coupling measurement indicated that the photorefractive polymers had the different charge-transporting species (hole or electron) for formation of internal space-charge field according to the chromophore structures. The correlation between NLO property and photorefractivity exhibited that the photorefractivities of the obtained polymers were strongly dependent on the NLO property rather than the photoconductivity.