LOW-TEMPERATURE ANOMALIES IN STRONG AND FRAGILE GLASS FORMERS

The low-temperature anomalies of glass forming systems are analyzed fo cusing on the concept of fragility. It is shown that two extremes on t he fragility plot, SiO2 and Ca0.4K0.6(NO3)(1.4), show a strong differe nce in specific heat in the range of excess vibrational contribution. This difference cannot be explained in the framework of the soft poten tial model in its present state. A relation between the excess vibrati onal contribution and the amount of structural fluctuations is suggest ed. It is shown that the suggested relation explains the found differe nce in low-temperature specific heat between strong and fragile glass formers.