Devitrification properties of vapor-deposited ethylcyclohexane glasses and interpretation of the molecular mechanism for formation of vapor-deposited glasses.

We constructed an adiabatic calorimeter adapted for the preparation and in situ thermal characterization of vapor-deposited glasses and reported the investigation of the enthalpic states and dynamic properties of ethylcyclohexane (ECH) glasses prepared by vapor deposition in the temperature range of (0.71–0.96)Tg,liq; Tg,liq = (101 ± 1) K is the calorimetric glass transition temperature of the bulk liquid. It was verified that the ECH glasses deposited at temperatures immediately below Tg,liq were characterized by lower enthalpies and higher devitrification temperatures (Tdev), as compared to the glass obtained by supercooling the bulk liquid. The deposition temperature (TD) expected to yield experimentally the entity with the highest Tdev and the lowest enthalpic state was estimated to be 0.93Tg,liq. A model potentially elucidating the fundamental mechanism of formation and devitrification for the glasses prepared via the physical vapor deposition method as a function of TD was proposed. The fundamental ...