Topological Model for the Viscosity of Multicomponent Glass‐Forming Liquids

Abstract

Topological constraint theory holds the key to understanding the temperature and composition dependence of the dynamics of glass‐forming liquids. Unfortunately, existing analytical models currently do not apply to multicomponent industrial glasses. Moreover, models that are strictly empirical in nature fail to provide insight into the underlying physical trends and cannot extrapolate beyond the compositional ranges used for fitting of their parameters. In this paper, we present a phenomenological model offering an improved description of the composition and temperature dependence of the shear viscosity of multicomponent liquids. The model has a clear physical foundation based on the temperature dependence of the network constraints with only two empirical fitting parameters per oxide component. The model predicts the isokom temperatures of 7141 viscosity measurements for 760 different compositions with a root‐mean‐square error of only 6.55 K.

Grand Challenges in Glass Science

“…Recent progress built upon topological constraint theory has improved descriptions of both the thermal and compositional effects on viscosity (Mauro et al, 2013b). However, more detailed investigations are required to understand the role of fragility (Angell, 1991), i.e., the steepness of the viscosity curve at the glass transition, in governing relaxation behavior and other properties such as diffusion, as well as the structural origin of the fragile-tostrong transition (Zhang et al, 2010) and any associated liquid-liquid critical point (Lascaris et al, 2014).…”

Bioactive Glass Innovations Through Academia‐Industry Collaboration

“…Constraint‐based models for the temperature and composition dependence of viscosity are already in routine use in industry . While accurate models exist for a variety of properties, liquidus temperature and crystallization behavior remains a significant challenge that would benefit from increased attention from academic research groups …”

Predictive model for the composition dependence of glassy dynamics

“…These values may be experimentally determined or calculated using temperature-dependent constraint theory, 36 as described in the following. These values may be experimentally determined or calculated using temperature-dependent constraint theory, 36 as described in the following.…”

“…29 However, here we seek to derive a model suitable for complex systems with many oxide components, so analytical derivation of T g (x) is, at least currently, not feasible. Therefore, based on our earlier work, 36 we express T g (x) as…”