Gradient index (GRIN) materials have many applications in optical fiber communication, imaging and optical instruments. Almost all GRIN optical fiber or lenses are made of glass, which has limitations due to poor flexibility, difficulty in processing and high price. Therefore, polymers are being investigated to produce a GRIN material that solves the problems of GRIN glass. In this study, the optical transmittance and refractive indices of three kinds of miscible copolymers of Methyl Methacrylate/Benzyl Methacrylate, Methyl Methacrylate/Trifluoro-ethyl Methacrylate and Benzyl Methacrylate/Trifluoro-ethyl Methacrylate were examined.