Academy of Sciences of the Czech Republic & University of Pardubice Joint Laboratory of Solid State Chemistry Studentská 84 Pardubice 532 10 Czech Republic Studentská 84 Pardubice 532 10 Czech Republic
National Institute for Research in Inorganic Materials, Science and Technology Agency of Japan Namiki 1-1 Tsukuba, Ibaraki 305 Japan Namiki 1-1 Tsukuba, Ibaraki 305 Japan
The volume and enthalpy relaxation rate of inorganic glasses and organic polymeric materials subjected to temperature jump T has been analyzed. It is shown that the relaxation behavior in isothermal conditions can be compared on the basis of the fictive relaxation rate defined as Rf=(dTf/dlogt)i. No significant difference between volume and enthalpy relaxation rate has been found for all materials examined. A simple equation relating the Rf and parameters of Tool-Naraynaswamy-Moynihan (TNM) phenomenological model has been derived. This equation predicts increasing Rf with the magnitude of temperature jump. It seems that correct determination of TNM parameters might be problematic for slowly relaxing polymers as the effect of these parameters becomes comparable with experimental uncertainty.