Optical elements derived from stretched glass

摘要

The physical elongation of a phase-separated glass by the application of a pulling stress to the glass above its softening temperature leads to a material with a number of interesting optical properties. This study is concerned with silver halide as the separated phase in an alkali-alumino- borosilicate glass. The initially spherically shaped halide particle is elongated into an elliptical shape by the action of the stretching process. As a consequence, the composite body acquires optical anisotropy exhibited as birefringence and dichroism. Experimental results show how the magnitude of the optical anisotropy can be related to shape anisotropy of the particles and, in turn, to the pulling stress. These results are discussed in terms of a simple polarizability model which adequately explains the results.