Determining the liquidus viscosity of glass-forming liquids through differential scanning calorimetry

Viscosity at the liquidus temperature (T_L), η_L, is a critical parameter for the design of new glasses, particularly for industrial glass production where crystallization must be suppressed. However, a direct viscometric determination of η_L for a glass-forming system is difficult due to crystallization. Here we propose an alternative approach for determining η_L through differential scanning calorimetry (DSC). Specifically, DSC is used to measure both the viscosity curve and liquidus temperature of a glass-forming system and then derive its η_L value. The η_L values determined using DSC are found to be in excellent agreement with those measured through viscometry. The DSC approach is applicable to various glass-forming systems covering a wide range of fragilities and η_L values spanning over five orders of magnitude. Other advantages of this approach are its accuracy and small sample requirements.