Chemical stability and structural changes in xNa2O-(45-x) B2O3-45P2O5-10MnO glasses influenced by Na2O

Borophosphate glasses with compositions xNa2O-(45-x) B2O3-45P2O5-10MnO, where x ranges from 5 to 25 mol%, have been prepared using the conventional melt quenching technique. Several methods including X-ray diffraction, Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC) have been used to characterize the produced materials. The absence of crystalline structure in the prepared phosphate glasses was confirmed by X-ray diffraction (XRD) studies. The chemical resistance of these glasses increases with the Na2O content. Glasses containing more than 15 mol% Na2O have excellent chemical resistance. The relationship between structural changes and composition was investigated by measuring density and glass transition temperature Tg. The results obtained show that the glass transition temperature and chemical properties increase with increasing sodium oxide composition in all the glasses studied. These experimental results indicate that Na2O lowers the melting point and increases the strength of the glasses.