Thermal analysis of Li2OTeO2 glass

The thermal properties of 0.30Li(2)O . 0.70TeO(2) glass are studied. Specific heat, C-p, is measured in the 170 degrees C < T < 270 degrees C interval. The Einstein temperature, theta(A) = 840 K, is determined from the temperature course of C-p. In the glass transition interval, the heat capacity undergoes an S-shaped transition from the value, C-gl, of the glass to that of undercooled melt, C-p. It is found that C-gl/C-p approximate to 0.62. The activation energy, E(T-f), for structural relaxation depends on a fictive temperature, T-f. For the glass under study, it is demonstrated that: E(T-f) = 655 + 300 (520/T-f - 1) kJ/mol. (C) 2000 Elsevier Science B.V. All rights reserved.