Two types of new photoresponsive polyester containing 4-cyanoazobenzene (CNAz) and 4-[4-(phenylazo)phenylazo]-o-cresol (DY7) moiety have been synthesized and their optical properties of the two polymer blend were evaluated. The polymers were synthesized from the reaction between azobenzene modified epoxy resin and isophthaloyl chloride. Thin films with good optical quality of each azobenzene modified epoxy resin, its polymer and its polymer blend were obtained by spin coating. The photoinduced birefringence (Dn) measurement was performed with excitation beams of 405 nm, 458 nm, and 488 nm. As a result, with increasing the DY7 content, the Dn was increased due to large intrinsic birefringence of DY7 that originates from extended p-conjugation and highly anisotropic structure of the moiety.