# Challenges of interpreting dielectric dilatometry for the study of pressure densification

## TL;DR

This study highlights the difficulties in using dielectric dilatometry to assess pressure densification in glass-forming materials, emphasizing the impact of cell geometry and dielectric properties on measurements.

## Contribution

It systematically investigates how dielectric cell geometry influences capacitance measurements during vitrification, revealing challenges in interpreting dielectric data for pressure densification.

## Key findings

- Capacitance depends on dielectric permittivity and cell geometry.
- Cell geometry significantly affects capacitance measurements.
- Data do not confirm pressure densification in 5-poly-phenyl-ether.

## Abstract

We report an experimental study documenting the challenge of employing dielectric dilatometry for the study of pressure densification in glass-forming materials. An influence of the dielectric cell geometry on the resulting capacitance of 5-poly-phenyl-ether upon vitrification under different thermobaric pathways is documented. The capacitive response is studied for two different multilayer capacitors: one with, in principle, fixed plate distance and one with Kapton spacers allowing for contraction/expansion. A combination of changes in the dielectric permittivity of the material and modifications of the capacitor geometry determines the final capacitance. We conclude that, in order to convert the measured capacitance to material density, it is of paramount importance to understand the geometry. The data presented do not make it possible to conclude on whether or not simple glass formers such as 5-poly-phenyl-ether can be pressure densified, but our work highlights the challenge of utilizing dielectric spectroscopy to tackle this problem effectively.