Mechanical relaxation in an ionic glass

Abstract

Abstract The modulus and loss tangent of a 45 mol% Ca (NO3)2:55 mol% KNO3 glass have been measured in the frequency range 10−4-100Hz, and in the temperature range 180–300 K, by using the torsional pendulum technique. One relaxation region with an internal friction of 10 −2 has been observed and this is attributed to the dielectrically inactive modes of ionic motions. The half-width of the spectrum is 4·3 decades, and its average relaxation rate has an Arrhenius dependence on temperature with an activation energy of 67kJmol−1. These features are qualitatively similar to those of the secondary relaxations observed in other types of glass. A thin film of ice formed by freezing of the moisture condensed on the surface of the glass sample causes a further relaxation at a relatively high temperature.