Viscosity of network liquids within Doremus approach

Defect-mediated diffusion and viscous flow of network forming liquids have been investigated. An analytical formula of viscosity has been derived with two-exponential forms demonstrating high activation energy at low temperatures and low activation energy at high temperatures with Arrhenius-type behavior for both high and low temperature limits. Calculated data for the viscosity of silica glass are in excellent agreement with the experimental data.