High throughput optimization procedure to characterize vitrification kinetics

Abstract

We present VITRIFAST, a high throughput optimization procedure to characterize the vitrification kinetics based on calorimetric measurements. By analyzing the temperature dependence of specific heat capacity, the method determines the fictive temperature, Tf, and the enthalpy change during physical aging, ΔH, within only a few seconds. We tested VITRIFAST on the low molecular weight glass-former o−terphenyl (OTP) and on an archetypal glass forming polymer, polystyrene (PS), by analyzing the outcome of two classical sets of experiments. By means of fast scanning calorimetry (FSC), we characterized the vitrification kinetics in a wide range of cooling rates and the isothermal physical aging after vitrification at a given rate. In less than 3 minutes, our method could process 18 different calorimetric scans and provided values of Tf and ΔH in excellent agreement with those reported in the literature. VITRIFAST can be employed in the analysis of the temperature dependence of any type of second order derivative of free energy and represents a tremendous advance in the data analysis of calorimetric scans. The method is particularly helpful for fast scanning calorimetry users, considering the extremely large number of heat capacity scans recorded by this technique within a few minutes.