Abstract:

To investigate the enthalpy relaxation behavior of maltitol glass system, differential scanning calorimetry (DSC) was used to obtain the specific heat capacity[C_p(T)] near the glass transition temperature(T_g) at different coo- ling rates ranged between 1 and 20 K/min. Three phenomenological models of enthalpy relaxation, Tool-Narayanaswamy-Moynihan(TNM) model, Adam-Gibbs-Vogel(AGV) model and Gómez Ribelles(GR) model, were used to simulate the experimental data. The models’ parameters were obtained via a curve-fitting method. The results indicate that TNM and AGV models gave the almost identical prediction powers and can reproduce the curves of experimental C_p(T) very well. However, the prediction power of GR model evolved from configurational entropyapproach is not so good as those of TNM and AGV models. In particular, the metastable limit state parameter(δ) introduced by Gómez Ribelles has insignificant effect on the enthalpy relaxation of the small molecular hydrogen-bonding glass system.

Key words: Differential scanning calorimetry(DSC), Maltitol, Glass transition, Enthalpy relaxation, Tool-Narayanas-wamy-Moynihan(TNM) model, Adam-Gibbs-Vogel(AGV) model, Gómez Ribelles(GR) model, Dynamic fragility