Structure and Electrical Conductivity of Glasses in the Na2O-Na2SO4-P2O5 System

The temperature-concentration dependence of the electrical conductivity of glasses in the Na2SO4-NaPO3 and Na2O-P2O5 systems has been investigated. Based on the obtained experimental data (IR spectra, density, microhardness, sound velocity, and paper chromatography), it has been demonstrated that SO42- ions form terminal groups through the incorporation into polyphosphate fragments of the structure of glasses in the Na2SO4-NaPO3 system. An increase in the electrical conductivity of glasses in this system by a factor of similar to 1000 (as compared to NaPO3) at 25 degrees 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-d of polar sulfate phosphate structural chemical fragments formed in the glass bulk upon introduction into sodium metaphosphate Na2SO4. This leads to an increase in the number of dissociated sodium ions, which are charge carriers, and to a decrease in the energy (E-a) of their activation shift in the sublattice formed by sulfate phosphate fragments of the structure.