Why is surface diffusion the same in ultrastable, ordinary, aged, and ultrathin molecular glasses?

Recently Fakhraai and coworkers measured surface diffusion in ultrastable glass produced by vapor deposition, ordinary glass with and without physical aging, and ultrathin films of the same molecular glass-former, N,N′-bis(3-methylphenyl)-N,N′-diphenylbenzidine (TPD). Diffusion on the surfaces of all these glasses is greatly enhanced compared with the bulk diffusion similar to that previously found by others, but remarkably Read more about Why is surface diffusion the same in ultrastable, ordinary, aged, and ultrathin molecular glasses?[…]

The dielectric signature of glass density

At present, we are witnessing a renewed interest in the properties of densified glasses prepared by isobaric cooling of a liquid at elevated pressure. As high-pressure densification emerges as a promising approach in the development of glasses with customized features, understanding and controlling their unique properties represent a contemporary scientific and technological goal. The results Read more about The dielectric signature of glass density[…]

The role of thermodynamic stability in the characteristics of the devitrification front of vapour-deposited glasses of toluene

Physical vapour deposition (PVD) has settled in as an alternative method to prepare glasses with significantly enhanced properties, providing new insights into the understanding of glass transition. One of the striking properties of some PVD glasses is their transformation into liquid via a heterogeneous mechanism that initiates at surfaces/interfaces. Here, we use membrane-based fast-scanning nanocalorimetry (104 K s−1) Read more about The role of thermodynamic stability in the characteristics of the devitrification front of vapour-deposited glasses of toluene[…]

high pressure

Ultrastable glasses portray similar behaviour to ordinary glasses at high pressure

Vapour deposited ultrastable glasses have gained much attention since its discovery in 2007 by the group of Mark Ediger. By physical vapour deposition, at proper deposition conditions, it is possible to obtain, in just few minutes, glasses with a thermodynamic stability that rivals the stability of glasses naturally aged for millions of years, i.e. ambers. Read more about Ultrastable glasses portray similar behaviour to ordinary glasses at high pressure[…]

Relaxation dynamics of glasses along a wide stability and temperature range

Up to this moment, the dynamics of glasses have been measured in a very short temperature range, limited by their time-scale. At low temperatures, the dynamics of glasses are too slow to be measured and at too high temperatures, the glass relax into the equilibrium supercooled state before being possible to extract any information by Read more about Relaxation dynamics of glasses along a wide stability and temperature range[…]