Effect of Na2SO4 substitution for Na2O on the structural and electrical properties of a sodium borophosphate glass

Abstract The effects of Na 2 SO 4 substitution to Na 2 O on the structural and electrical properties of a sodium borophosphate glass system prepared by the melt/quenching method were investigated by means of different techniques. The amorphous nature of the glass was evidenced by X-ray diffraction (XRD). Differential scanning calorimetry (DSC) has showed a decrease of glass transition temperature ( T g ) while density measurements showed an increase of the molar volume V m of the glass with the addition of Na 2 SO 4 . Raman and infrared (FTIR) spectroscopies have revealed a significant structural change which confirms the behavior of T g and V m of the glass. Impedance measurements showed that the overall electrical behavior originates from bulk contribution, whereas the frequency dependence of ac conductivity does not seem to follow the simple Jonscher's power law due to the electrode polarization effects. Moreover, the dc conductivity exhibits an Arrhenius-type behavior with temperature. The decrease of the activation energy and the increase of the electrical conductivity with the addition Na 2 SO 4 was discussed based on the results of the structural investigation of the glass.