Thermal analysis of Li2O TeO2 glass

The thermal properties of 0.30Li2O 0.70TeO2 glass are studied. Speci®c heat, Cp, is measured in the 170°C < T < 270°C interval. The Einstein temperature, hA ˆ 840 K, is determined from the temperature course of Cp. In the glass transition interval, the heat capacity undergoes an S-shaped transition from the value, Cgl, of the glass to that of undercooled melt, Cp. It is found that Cgl=Cp 0:62. The activation energy, E…Tf†, for structural relaxation depends on a ®ctive temperature, Tf . For the glass under study, it is demonstrated that: E…Tf† ˆ 655‡ 300…520 Tf ÿ 1† kJ/ mol. Ó 2000 Elsevier Science B.V. All rights reserved.