Solution calorimetric study of mixing enthalpy in 0.8[xB2O3-(1 − x)SiO2]-0.2K2O glasses at 298 K

The mixing enthalpies in the 0.8[xB2O3-(1 − x)SiO2]-0.2K2O glassy system with 0 ≤ x ≤ 1 have been deduced from accurate calorimetric measurements of solution enthalpies in acidic solvent at 298 K. The substitution of SiO2 by B2O3 corresponds to a negative enthalpic effect and suggests the absence of some glassy miscibility gap. The mixing enthalpies are of the same order of magnitude as mixing enthalpies usually found in molten salts.