Kinetic Study and Optical Investigations of some TeO<sub>2</sub>-GeO<sub>2</sub> Glasses

On the basis of DTA analyses of 0.9TeO 2 - 0.1GeO 2 and 0.8TeO 2 - 0.2GeO 2 glasses, the Avrami parameters were determined to be 3 indicating that the mechanism for the crystallization is bulk crystallization. DTA analyses were carried out at different heating rates and two crystallization peaks were observed for both of the glass compositions. The crystallization activation energies were determined by using the variation of peak temperatures with the heating rate. The absorption spectra measured between 300 - 800 nm wavelength region were used to determine the optical band-gap and Urbach energies of the glasses. It is found that they both are a function of glass composition.