Liquid fragility determination of oxide glass-formers using temperature-modulated DSC

Glass-forming liquids exhibit a pronounced diversity in the viscosity-temperature relation. This has been characterized by the liquid fragility index to quantify the extent of the non-Arrhenian flow. Precise and accurate determination of liquid fragility is important for understanding a range of phenomena and controlling industrial glass melting processes. In this study, we use temperature-modulated differential scanning calorimetry (TM-DSC) to determine liquid fragility of a wide range of oxide compositions, including tellurites, borates, and silicates. We compare our fragility data to those determined using viscometry and the Moynihan DSC approach. We find that TM-DSC is a useful method for determination of fragility, as it exhibits higher sensitivity and provides an easier and more reliable determination of characteristic temperatures compared to the Moynihan approach. Moreover, TM-DSC is faster and requires smaller sample volume compared to the viscometric approach. However, we also observe that TM-DSC tends to either overestimate or underestimate the fragility of very strong and highly fragile compositions, respectively.