| Popis: |
Birefringence caused by loading uniaxially oriented PMMA samples in the glassy state, has been studied. The increase in the anisotropic properties of the polymer with increasing extent of stretching was evaluated from the coefficient of optical sensitivity to stress. A substantial on the value and sign of the birefringence of chemical and physical bonds, related effect on the value and sign of the birefringence of chemical and physical bonds, related to the stress distribution in the sample volume, has been found. The nature of the negative pathlength difference during elastic deformation of PMMA and the reason for changes in the picture of frozen bands in the material, with a decrease in temperature, are discussed. |
