Enthalpy and high temperature relaxation kinetics of stable vapor-deposited glasses of toluene

In situ investigation of vapor-deposited glasses of toluene and ethylbenzene via alternating current chip-nanocalorimetry.

Vapor-deposited glasses of toluene and ethylbenzene have been characterized by in situ ac chip-nanocalorimetry. The high sensitivity of this method allows the detection of small changes in the heat capacity of nanogram size samples. We observe that vapor-deposited glasses have up to 4% lower heat capacities than the ordinary glass. The largest heat capacity decrease and the most kinetically sta...

Origin of Ultrastability in Vapor-Deposited Glasses.

Glass films created by vapor-depositing molecules onto a substrate can exhibit properties similar to those of ordinary glasses aged for thousands of years. It is believed that enhanced surface mobility is the mechanism that allows vapor deposition to create such exceptional glasses, but it is unclear how this effect is related to the final state of the film. Here we use molecular dynamics simul...

Thermodynamics of Enthalpy Relaxation and Hole Formation of Polymer Glasses

Thermal stability of vapor-deposited stable glasses of an organic semiconductor.

Vapor-deposited organic glasses can show enhanced kinetic stability relative to liquid-cooled glasses. When such stable glasses of model glassformers are annealed above the glass transition temperature Tg, they lose their thermal stability and transform into the supercooled liquid via constant velocity propagating fronts. In this work, we show that vapor-deposited glasses of an organic semicond...

Vapor-deposited glasses provide clearer view of two-level systems.

Glasses and crystals play different roles in technology. When precise control of local structure is required, as in silicon-based electronics, crystals are used. On the other hand, when macroscopic homogeneity is required, as in optical fibers, glasses are used. The pairing of local disorder and macroscopic homogeneity in glasses is not a coincidence. The range of local packing arrangements pre...