TRANSPARENT ZERO-BIREFRINGENCE COPOLYMER AND ITS OPTICAL-PROPERTIES

Birefringence is caused by both orientation of polymer chains and phot oelasticity. These birefringences were compensated by random copolymer ization of negative birefringent methyl methacrylate and positive bire fringent benzyl methacrylate, but orientational and photoelastic zero birefringences were achieved with quite different compositions of the copolymers. Note that the birefringence of the copolymer that occurred in the process of injection molding was almost completely eliminated with a composition for orientational zero birefringence. The orientati onal and photoelastic zero-birefringence copolymers possessed enough t ransparency as optical materials that the total scattering losses were 30.4 and 19.5 dB/km, respectively, competing with the transparency of homopolymers. (C) 1997 0ptical Society of America.