ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
We report spontaneous Brillouin and photon correlation spectroscopic results on the dynamics of the local density fluctuations in the ionic mixed salt xKNO3⋅yCa(NO3)2 with molar ratios 2:1, 3:2, and 1:1. For these mixtures, the density relaxation function g(t) changes from a stretched exponential (β=0.47) near the glass transition temperature Tg, to an exponential (β=1) form at high temperatures, whereas the composition dependence of the relaxation time τ reflects mainly differences between the Tg values. The 3:2 fragile glass (Tg=60 °C) is one of the few examples where g(t) is now known from the glass-like (60–90 °C) to the liquid-like (T〉100 °C) region through the application of various dynamic scattering techniques. The τ(T) and the evolution of the width β of the distribution are discussed in terms of the physical pictures implied by current models of the liquid and glass transition phase.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.460731
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