THERMAL-PROPERTIES OF CHALCOGENIDE-HALIDE GLASSES IN THE SYSTEM - GE-S-I

Chalcogenide-halide glasses in the series [Ge0.3S0.7]100-xIx where 0 less-than-or-equal-to x less-than-or-equal-to 30 have been prepared and have potential applications as short length infrared optical fibres. As x is increased the expansion coefficient increases, in addition the glass transformation temperature and onset temperature of mass loss both decrease as determined by differential scanning calorimetry and thermogravimetry, respectively. Melt viscosities in the range 10(7)-10(10.7) Pa s have been determined via penetration viscometry and isoviscous points are at lower temperatures as x increases. These results have been discussed in relation to known structural information and the fragility of the melts has been compared. Predicted fibre drawing temperatures tend to lie close to the onset of mass loss.