The presence of an optically anisotropic body between crossed polarizers generally results- in the transmission of light. This has been used to study the rate of crystallization of spherulitic polymers1,2. For the method to be applicable, it-is necessary that the sample be thin and be examined in sufficiently early stages of crystallization so that spherulitic -overlap is negligible. Also, the sample must have no macroscopic orientation. All of the transmission should be a consequence of the presence of spherically or circularly symmetrical anisotropic bodies and should not result from any overall anisotropy. Also, the existing derivations1 are two dimensional in nature.
展开▼
