$\alpha$- and $\beta$- Relaxation Dynamics of a fragile plastic crystal

TL;DR

This study investigates the dielectric relaxation dynamics of the fragile plastic crystal Freon112, revealing its unique $eta$-relaxation behavior and the influence of molecular conformations on its glassy state.

Contribution

It provides new insights into the relaxation processes of Freon112, highlighting the role of multiple molecular conformations in its dynamic behavior.

Findings

Freon112 exhibits a strong $eta$-relaxation.

Freon112 is classified as a relatively fragile plastic crystal.

Presence of two molecular conformations influences its relaxation dynamics.

Abstract

We present a thorough dielectric investigation of the relaxation dynamics of plastic crystalline Freon112, which exhibits freezing of the orientational degrees of freedom into a glassy crystal below 90 K. Among other plastic crystals, Freon112 stands out by being relatively fragile within Angell's classification scheme and by showing an unusually strong $\beta$-relaxation. Comparing the results to those on Freon112a, having only a single molecular conformation, points to the importance of the presence of two molecular conformations in Freon112 for the explanation of its unusual properties.