Optical modulation of the refractive index in the glass transition range

The phenomena accompanying the effect revealed earlier that manifests itself as a peak of the intensity of light scattered at an angle of 90degrees and is universally observed in the glass transition range of oxide glasses are investigated. It is shown that the development of this peak is attended by the appearance of the diffraction pattern in the vicinity of the light beam passing through the sample. This effect is associated with the formation of Deltan gratings in the sample bulk due to the interaction of a low-intensity laser radiation with a highly unstable glass structure. The glass samples with a spatially modulated refractive index have been prepared by the quenching technique.