Thermodynamical miscibility in 0.8[xB2O3–(1 − x)P2O5]–0.2K2O glasses

The thermodynamical miscibility in 0.8[xB2O3–(1 − x)P2O5]–0.2K2O glasses has been studied by measuring the glass transition temperature and the mixing enthalpy. Measurements have been performed by differential scanning calorimeter and hydrofluoric acid solution calorimetry at 298 K. The enthalpies of mixing are significantly negative over the whole range of composition. The results are discussed in terms of intermolecular associations.