Effect of glass composition on activation energy of viscosity in glass-melting-temperature range

In the high-temperature range, where the viscosity (η) of molten glass is < 103 Pa s, the activation energy (B) is virtually independent of temperature (T). Moreover, the coefficient A in the Arrhenius relationship, ln(η) = A + B/T, is nearly independent of melt composition. Hence, the viscosity–composition relationship for η < 103 Pa s is defined by B as a function of composition. Using a database encompassing over 1300 compositions of high-level waste glasses with nearly 7000 viscosity data, we developed mathematical models for B(x), where x is the composition vector in terms of mass fractions of components. In this paper, we present 13 versions of B(x) as first- and second-order polynomials with coefficients for 15 to 39 components, including Others, a component that sums constituents having little effect on viscosity.

► We have developed 1st and 2nd order models for viscosity of nuclear waste glasses. ► Our models are based on nearly 7000 data. ► Activation energy is a single factor determining viscosity–composition relationship at < 103 Pa s. ► Measured-calculated deviation of data exhibits a near-Gaussian distribution.