Photorefractive Organic Polymer System Functionalized with a Nonlinear Optical Chromophore Boronate Derivative

by J. L. Maldonado et al. AZojomo, November 2005 The preparation and characterization of organic photorefractive polymer composites derived from (2-(p-chlorophenyl)-(3'-nitrobenzo[d])-(4"-methoxybenzo[h])-1,3-dioxa-6-aza-2-boracyclonon-6-ene, a push-pull boronate, which shows NLO properties, are described. The polymers are based in the photoconductor poly(9-vinylcarbazole) and the plasticizer 9-ethylcarbazole PVK:ECZ matrix, and C₆₀ as sensitizer. For the photorefractive performance, two different chromophore concentrations were used, in addition, the ratio of PVK:ECZ was varied to see the effect on the room temperature molecular orientation. Holographic experiments in a tilted four and two wave mixing geometry were performed by using a 10 mW He-Ne laser (632.8 nm). The experiments were performed at room temperature, with a fixed grating spacing L of 2.9 mm, for determining the electric field steady-state diffraction efficiency dependency and the optical gain of the composites. Acceptable photorefractive properties were observed for a polymer with a glass transition temperature T_g of 77°C. Even at this T_g, the response time was less than one second. Read more