Effect of composition and structural factors on the viscosity of borosilicate glasses and melts

The features of the effect of the composition and structure of glasses of the systems Na₂O – CaO – B₂O₃ – SiO₂ and Na₂O – CaO – B₂O₃ – Al₂O₃ – SiO₂ on the temperature curve of the viscosity in the 10¹⁰ – 10⁴ Pa · sec range were established. The important effect of phase separation processes—liquation and crystallization—on the viscosity indexes in the temperature region of the transition from the plastic to the liquid state was demonstrated.