Abstract
Some physical and optical properties of xPbF(2).(100-x)TeO2 (0 <= x <= 90 mol%) glasses and glass-ceramics have been studied. Density increases linearly with increasing PbF2 content up to 70 mol% PbO, then tends to be constant for 70 < PbF2 <= 90 mol%. The molar volume remains constant in the first region then increases for PbF2 > 70 mol%. The main factor which controls the molar volume is the change in free volume and packing density. There is a limited increase in conductivity with increasing PbF2 content then it decreases for PbF2 >= 50 mol%. Pb2+ ions are the main charge carriers. The band gap E-g and the linear refractive index n change in an opposite manner where E-g increases with increasing PbF2 content for PbF2 <= 50 mol%, then it decreases sharply for PbF2 > 70 mol%. For PbF2 <= 50 mol%, the Urbach energy E-U decreases then seems to be constant for further additions. Metallization criterion M and molar refractivity R-m change in a similar manner to E-g and n, respectively.