CONDUCTIVITY RELAXATION PARAMETERS OF SOME AG+ CONDUCTING TELLURITE GLASSES CONTAINING AGI OR THE (AGI)(0.75)(TLI)(0.25) EUTECTIC MIXTURE

The conductivity relaxation parameters of some Ag+ conducting tellurit e glasses containing either AgI or the (AgI)(0.75)-(TII)(0.25) eutecti c mixture have been determined from an analysis of ac conductivity dat a measured in a wide temperature range. Transport properties in these materials appear as due to an Ag+ ion hopping mechanism. The stretched exponential function exp-(t/tau(sigma))(beta) has been used to descri be the conductivity relaxation. The relaxation parameters have been in vestigated as a function of the AgI rate. The results obtained are sho wn to be in good agreement with the predictions of the Ngai coupling m odel. A correlation has been also established for the glasses investig ated between the stretched exponent beta of conductivity relaxation fu nction with the decoupling index R(tau)(T-g), proposed by Angell, wher e R(tau)(T-g) is the tau(s)/tau(sigma) ratio of the average structural and conductivity relaxation times at the glass transition temperature T-g.