DENSITY OF TUNNELING STATES AND POTENTIAL-ENERGY LANDSCAPES OF GLASSES

Evidence of a correlation between the density of two-level systems and the fragility of glasses are presented for a variety of glasses. More fragile glasses tend to have higher excess low temperature specific h eat (T < 1 K) and thus higher density of tunneling states. This correl ation can be explained in terms of the different topography of potenti al energy landscapes between strong and fragile glasses in the configu ration space.