ポリマーの人工複屈折とその成分の正負性

抄録

The variational quantity of principal refractive index and the birefringence of polymers during the creep under a constant stress and at a constant temperature were investigated in the temperature range from -100°C to 120°C using the Mach-Zehnder interferometer and photoelectric method. In the present study, it can be found that the birefringence N of polymers consists of two components with the sign of positive or negative. Namely, two components are the instantaneous birefringence NE which appears in the moment after loading and the delayed birefringence NR which appears as loading time goes by. It is understood that NE is due to the perfect elasticity in the moment after loading and NR originated with the retarded elasticity. Thus, birefringence behaviors of polymers are classified into four types of properties by combinations of signs. These classified properties are as follows. Types 1: NE +, NR +, N=NE+NR +, Types 2: NE +, NR -, N=NE+NR +→0→- (as loading time goes by), Types 3: NE -, NR +, N=NE+NR -→0→+ (as loading time goes by), Types 4: NE -, NR -, N=NE+NR -, (+: positive, -: negative). Moreover, visco-elasto-plastic stresses and strains in polymers and aluminum metal plates were analyzed with relations among loading time, birefringence, stress and strain which were obtained from tensile creep testings for birefringences and strains of these materials.