We have performed depolarized dynamic light scattering (photon correlation) measurements on the ionic glass forming mixture 2Ca(NO3)2sdot;3KNO3above its glass transition in the temperature range 68ndash;86thinsp;deg;C. We find the relaxation function is a stretched exponential. The average relaxation time follows an Arrhenius temperature dependence and can be related to motions on a molecular scale. The width parameter bgr; does not vary with temperature and is bgr;=0.40plusmn;0.05. Combination of our bgr; data with other literature values shows that bgr; evolves with temperature over a larger range. At high temperature, bgr; crosses over from bgr;=1 to bgr;1 at a temperature which matches well with where the viscosity first deviates from a power law behavior. bgr; then evolves downward with lowering temperature and then settles at 0.4 roughly 30thinsp;deg;C above the glass transitionTg. This behavior corresponds well with recent theory relating the glass transition to the ramification of phase space but it implies that the percolation of phase space occurs well aboveTg.
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