IONIC-CONDUCTIVITY AND STRUCTURE OF THALLIUM TELLURITE GLASSES CONTAINING AGI

The ionic conductivities of [TeO2: RTlO0.5](1-x)[AgI](x) glasses have been determined and compared with those of compositions [TeO2: RAgO0.5 ](1-x)[AgI](x). The conductivity increases when x(AgI) increases, but lower conductivities are observed for glasses based on thallium tellur ite than for those based on silver tellurite. It is concluded from the conductivity variation with the glass composition that the ionic cond uctivity properties are bound essentially to the mobility of the Ag+ i ons located in an iodide environment. The IR and Raman spectra of tern ary [TeO2: RTlO0.5](1-x)[AgI](x) glasses show only small modifications of the tellurite network, irrespective of the amount of AgI introduce d into the binary glasses. The existence of intermediate-range order i n these materials is discussed.