Non-Newtonian viscous flow in soda-lime-silica glass at forming and annealing temperatures

Abstract

Viscous flow was measured at high shear rates by fiber elongation and cone-plate rheometry. Non-Newtonian viscosity data were taken from 10 6 to 10 14 P between 533 and 810°C on 2 soda-line-silica glasses of similar composition. The results show that the viscosity shear thinning effect can be scaled to a universally applicable behavior by assuming that the glass has a temperature-dependent limiting strength which decreases with the viscosity. This weakening of the structure with increasing temperature results in the appearance of shear thinning effects at lower strain rates than predictedby relaxation time scaling alone.