ANNEALING OF A GLYCEROL GLASS - ENTHALPY, FICTIVE TEMPERATURE AND GLASS-TRANSITION TEMPERATURE-CHANGE WITH ANNEALING PARAMETERS

The enthalpy change (relaxation enthalpy) of the glycerol glass with a nnealing time was studied using DSC for different annealing temperatur es. The investigation of the fictive temperature and glass transition temperature variations with annealing parameters was also carried out. In this study, a well-annealed glass was used as a reference for the determination of relaxation enthalpy. Two enthalpy contributions to re laxation enthalpy were observed. The results were discussed in terms o f a multi-step thermodynamic transformation of molecular associations in the glass transition range. A linear relation was also found betwee n relaxation enthalpy and fictive temperature. This well-known conclus ion was established from experimental results. Finally, an empirical r elation was proposed for the variation of the fictive temperature with annealing parameters. (C) 1997 Elsevier Science B.V.