Light-Induced Anisotropy in Azobenzene Doped Copolymer Films

Abstract

In this study, an azobenzene dye, Dispersion Red 1 (DR1) was doped into the copolymers of methyl methacrylate(MMA) and butyl acrylate(BA) to obtain five bulk composites with varied ratios of methyl methacrylate to butyl acrylate. An experimental setup, in which the He-Ne laser produced signal beams and Ar+ laser, the pump beams was employed to investigate the photoinduced anisotropic properties of these samples. The results show that, the lower rigidity of the copolymers chains caused by the increased BA content would lead to a lower extent of birefringence for the samples. With the increased pump beam power, the extent of birefringence first slightly increased, reached a maximum value, and then decreased. These increases and then decreases would be caused by the co-effects of both orientation and saturation mechanism. On the other hand, the optical dichroism properties can be detected in the bulk samples with photoinduced anisotropic property. The birefringence and dichroism properties exhibited by the dye-doped bulk composites have great potential in optical devices and optical communication systems; in particular, these bulk polymeric materials are very important for three-dimensional optical applications.