Structure and electrical conductivity of glasses in the Na^sub 2^O-Na^sub 2^SO^sub 4^-P^sub 2^O^sub 5^ system

The temperature-concentration dependence of the electrical conductivity of glasses in the Na^sub 2^SO^sub 4^-NaPO3 and Na^sub 2^O-P^sub 2^O^sub 5^ systems has been investigated. Based on the obtained experimental data (IR spectra, density, microhardness, sound velocity, and paper chromatography), it has been demonstrated that SO^sub 4^^sup 2-^ ions form terminal groups through the incorporation into polyphosphate fragments of the structure of glasses in the Na^sub 2^SO^sub 4^-NaPO3 system. An increase in the electrical conductivity of glasses in this system by a factor of 1000 (as compared to NaPO3) at 25°C and a decrease in the activation energy for electrical conduction from 1.40 to 1.10 eV have been interpreted from the viewpoint of the decrease in the dissociation energy E ^sub d^ of polar sulfate phosphate structural chemical fragments formed in the glass bulk upon introduction into sodium metaphosphate Na^sub 2^SO^sub 4^. This leads to an increase in the number of dissociated sodium ions, which are charge carriers, and to a decrease in the energy (E ^sub a^) of their activation shift in the sublattice formed by sulfate phosphate fragments of the structure.[PUBLICATION ABSTRACT]