The transmission of light by films of crystalline polymers

The transmission of polarized light by films of crystalline polymers depends on the size, shape, orientation, anisotropy, and arrangement of the constituent crystallites. Its measurement as a function of the polarization direction of the incident light and that of the analyzing polarization filter characterizes the structure. This may be readily followed during the crystallization or deformation of the polymer. The transmission depends upon some of the same optical parameters as does the scattering and provides complementary information. The scattering, measured as a function of angle, is capable of providing more information than the transmission but its measurement during rapid processes is more difficult. The utility of these techniques is illustrated for the isothermal crystallization of oriented polyethylene films and for the stress‐induced crystallization of rubber.