Viscosity, Free Activation Energy, and Glass Transition Temperature of Potassium Boron K₂O–B₂O₃ Melts

Abstract—The viscosity of potassium–boron melts is measured in the temperature range 918–1699 K using a vibrational viscosimeter. The content of potassium oxide is varied from 0.74 to 28.46 mol %. The parameters of the viscous flow in melts (the configuration–activation energy(ε_h) and the shifting energy of the bridging oxygen atoms’ bonds (U_∞)) using the configuration–activation model are calculated for two temperature intervals 918–1400 K and 1400–1699 K. The glass transition temperature (T_g) is measured by differential scanning calorimetry (DSC) and the concentration dependence of the glass transition temperature on the content of potassium oxide in the melt is shown.