Heterogeneous dynamics of prototypical ionic glass CKN monitored by physical aging.

In this Letter, we investigate the time evolution of the conductivity relaxation process in a prototypical ionic glass former, [Ca(NO(3))(2)](0.4)[KNO(3)](0.6) (CKN), undergoing physical aging. It is demonstrated that the heterogeneous nature of molecular dynamics is manifested by an increase in the slope of the high frequency wing of the conductivity relaxation peak as the sample is annealed below the glass transition temperature. This finding is also confirmed for other ionic glass formers. Additionally, we analyze the kinetics of the change in the ionic conductivity in glassy CKN to probe its structural relaxation.