Universal behavior of the apparent fragility and the structural relaxation time for the high pressure previtreous effect

TL;DR

This paper demonstrates a universal pressure-related behavior of apparent fragility and structural relaxation times in glass-forming materials, deriving a relation that accurately models experimental data across various substances and pressures up to 2.2 GPa.

Contribution

It introduces a new 3-parameter relation to describe the previtreous behavior of relaxation times, applicable across different materials and pressure ranges.

Findings

Universal pressure-related fragility behavior observed.

Derived a 3-parameter model fitting experimental data.

Effective up to pressures of 2.2 GPa.

Abstract

This report shows the universal previtreous behavior of the pressure related apparent fragility, i.e. the steepness index Basing on this finding, the 3-parameter relation for portraying the previtreous behavior of the primary (structural) relaxation time is derived. The fair portrayal of experimental data was shown for glass forming 8*OCB (liquid crystal), EPON 828 (resin) and diisobutyl phthalate, propylene carbonate (low molecular weight liquids). On decompressing, the dynamic crossover dynamic domains is clearly detected. All these recalls the mode-coupling-theory behavior, but for the pressure path. It is notable, the discussed description offers the fair portrayal of experimental data even in the extreme pressure range P up to 2.2 GPa.