Agi-Ag oxysalt glasses : review of thermodynamic and transport properties

The transport and thermodynamic properties of AgI-Ag oxysalt(s) glass forming systems are reviewed with the aim to attain an overall interpretation which may be applied to all of them as well as to analogous systems. The halide hosted in these glasses is the main source of mobile ions, whereas the oxyanionic environment determines the width of the glass forming region, as well as the glass transition temperature, Tg, of the glass. Thermoelectric power data of silver electrode thermocells allow evaluation of the molar entropy, S(Ag+). S(Ag+, T = Tg) depends on the glass composition, N(Ag+), [N stands for equivalent fraction] just as expected for a regular binary mixture. One is therefore inclined to guess that these glasses would host silver ions in two different kinds of sites, e.g., either totally coordinated by halide ions or between halide and oxyanions. This conclusion should be taken into account for designing other glasses where silver is replaced by copper or lithium ions.