CONDUCTIVITY RELAXATION IN SILVER-IODIDE SILVER BORATE GLASSES

Conductivity relaxation in ionically conducting glasses of composition (AgI)x(Ag2O:2B2O3)1-x, where x = 0 and 0.6 has been studied. The complex capacitance was measured in the frequency range 10(-3)-10(6) Hz at temperatures for which the contribution of electrode polarisation to the dielectric response was found to be negligible. The dc conductance, the exponent n which describes the power law behaviour of the conductance at high frequencies, as well as the very-high-frequency capacitance, were determined without any assumption on the shape of the relaxation function. The power-law exponent, n, was found to be 0.72-0.75, which is close to the prediction of percolation theory and indicates that ion conduction takes place on a conducting network. From the experiments, the inverse loss tangent, which is very sensitive to the form of the relaxation function, was also determined. The data are in good agreement with the empirical Davidson-Cole relaxation function.