A new interpretation of dielectric data in molecular glass formers

TL;DR

This paper proposes a new interpretation of dielectric data in molecular glass formers, suggesting that dielectric relaxation involves multiple structural and thermodynamic processes beyond molecular orientation.

Contribution

It introduces an alternative to the traditional Debye-based models by linking dielectric relaxation to entropy, short-range order, and density relaxation.

Findings

Dielectric relaxation is faster than Debye prediction but slower than shear modulus breakdown.

Dielectric relaxation involves entropy, short-range order, and density changes.

Proposes a new model replacing the Gemant-DiMarzio-Bishop extension.

Abstract

Literature dielectric data of glycerol, propylene carbonate and ortho-terphenyl (OTP) show that the measured dielectric relaxation is a decade faster than the Debye expectation, but still a decade slower than the breakdown of the shear modulus. From a comparison of time scales, the dielectric relaxation seems to be due to a process which relaxes not only the molecular orientation, but the entropy, the short-range order and the density as well. On the basis of this finding, we propose an alternative to the Gemant-DiMarzio-Bishop extension of the Debye picture.