What is it about?

A system is at equilibrium when its properties do not change with time. Experience tells us that such observation is, however, rarely encountered in nature. Since almost a century, we know that macroscopic phenomena of equilibration require microscopic motion of molecules. Our laboratory has recently discovered that molecules can equilibrate via a type of motion called the Slow Arrhenius process, SAP. In this paper, we show that the energy barrier that molecules need to overcome to move via the SAP does not depend on temperature, nor on the volume of the material.

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Why is it important?

While the molecular origin of the SAP is still under debate, we show that simple mathematical modeling permits extending the investigation of this new process to temperatures much lower than those previously investigated. The outcome of our analysis allowed us to verify that the SAP has nothing to do with the so-called secondary processes of the glassy state. These results contribute in defining the nature of this elusive process.


Working on this article was particularly stimulating. We combined experimental and modeling skills and we were thrilled to see how, by means of simple ideas, we could reproduce the behavior of complex systems.

Simone Simon Napolitano
Universite Libre de Bruxelles

Read the Original

This page is a summary of: Tracing the slow Arrhenius process deep in the glassy state–quantitative evaluation of the dielectric relaxation of bulk samples and thin polymer films in the temperature domain, The Journal of Chemical Physics, January 2024, American Institute of Physics,
DOI: 10.1063/5.0184382.
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