Supercooled liquids and the glass transition

Abstract

Glasses are disordered materials that lack the periodicity of crystals but behave mechanically like solids. The most common way of making a glass is by cooling a viscous liquid fast enough to avoid crystallization. Although this route to the vitreous state-supercooling-has been known for millennia, the molecular processes by which liquids acquire amorphous rigidity upon cooling are not fully understood. Here we discuss current theoretical knowledge of the manner in which intermolecular forces give rise to complex behaviour in supercooled liquids and glasses. An intriguing aspect of this behaviour is the apparent connection between dynamics and thermodynamics. The multidimensional potential energy surface as a function of particle coordinates (the energy landscape) offers a convenient viewpoint for the analysis and interpretation of supercooling and glass-formation phenomena. That much of this analysis is at present largely qualitative reflects the fact that precise computations of how viscous liquids sample their landscape have become possible only recently.

The jamming scenario—an introduction and outlook

“…There is no doubt that the time scale for relaxation increases dramatically (faster than an Arrhenius law for what are called "fragile" glasses) as the temperature is lowered from the melt towards the glass transition temperature, T g , but it is much less clear whether there are any static growing length scales that can be identified that accompany the slowing down [128,129]. However, as is well-documented in this book, there is a growing length scale associated with heterogeneities in the dynamics, which become increasingly collective as the viscosity increases.…”

Supercooled liquids with enhanced orientational order

“…Depending on their energy landscape and on the thermodynamic and kinetic path they follow, they acquire a periodic structure with full translational order (crystals) or maintain a morphology lacking in long-range order (glasses) [2][3][4][5] . The structural relaxation time increases upon cooling, and the glassy state is achieved when t exceeds the experimental observation time; upon quenching, this condition occurs at the glass transition temperature, T g .…”

Properties of Bulk Metallic Glasses

“…При этом вязкость расплава при охлаждении до температуры стеклования [5] ме-няется от ~10 -3 до 10 12 Па·с. Процесс структурной релаксации [6,7] при нагреве до температуры сте-клования/расстекловывания приводит к повыше-нию плотности и вязкости металлического стекла [8], его охрупчиванию (с некоторыми исключени-ями [9]) и изменению многих других свойств.…”