Glassy materials display numerous important properties which relate to the presence and intensity of secondary ($\ensuremath{\beta}$) relaxations that dominate dynamics below glass transition temperature. However, experimental protocols such as annealing allow little control over $\ensuremath{\beta}$ relaxation for most glasses. Here we report on toluene in highly stable glasses prepared by physical vapor deposition. At conditions generate highest kinetic stability, about 70% is suppressed,...

In situ dielectric spectroscopy has been used to characterize vapor-deposited glasses of methyl-$m$-toluate (MMT), an organic glass former with low fragility ($m=60$). Deposition near $0.84{T}_{g}$ produces very high kinetic stability; these materials are comparable in stability the most stable produced from more fragile formers. Highly MMT, when annealed above ${T}_{g}$, transform into supercooled liquid by a heterogeneous mechanism. A constant velocity propagating front is initiated at...

Glasses of ethylcyclohexane produced by physical vapor deposition have been characterized in situ alternating current chip nanocalorimetry. Consistent with previous work on other organic molecules, we observe that glasses high kinetic stability are formed at substrate temperatures around 0.85 Tg, where Tg is the conventional glass transition temperature. Ethylcyclohexane least fragile glass-former for which stable formation has established. The isothermal transformation vapor-deposited into...

In situ AC nanocalorimetry was used to characterize vapor-deposited glasses of six mono- and di-alcohol molecules. Benzyl alcohol with high kinetic stability decreased heat capacity were prepared. When annealed above the glass transition temperature Tg, transformation these into supercooled liquid took 103.4 times longer than relaxation time (τα). This is similar other highly stable organic prepared by vapor deposition first clear demonstration an forming a glass. Vapor deposited five...

The reversing heat capacity of vapor-deposited o-terphenyl glasses was determined by in situ alternating current nanocalorimetry. Glasses were deposited at substrate temperatures ranging from 0.39 Tg to Tg, where is the glass transition temperature. near 0.85 exhibited very high kinetic stability; a 460 nm film required ∼104.8 times structural relaxation time equilibrium supercooled liquid transform into state. For most stable glasses, lower than that ordinary liquid-cooled (1 ± 0.4)%; this...

AC chip nanocalorimetry is used to characterize vapor-deposited glasses of methyl-m-toluate (MMT). Physical vapor deposition can prepare MMT that have lower heat capacity and significantly higher kinetic stability compared liquid-cooled glasses. When heated, highly stable transform into the supercooled liquid via propagating fronts. We present first quantitative analysis temporal spatial uniformities these transformation The front velocity varies by less than 4% over duration transformation....

Recent work has shown that diffusion and crystal growth can be much faster on the surface of molecular glasses than in interior enhancement effect varies with size intermolecular hydrogen bonds (HBs). In a related phenomenon, some molecules form highly stable when vapor-deposited, while others (notably those forming extensive HBs) do not. Here we examine all available data these phenomena for quantitative structure-property relations. For systems no HBs, coefficient Ds decreases increasing d...

Physical vapor deposition (PVD) has been used to prepare organic glasses with very high kinetic stability and it suggested that molecular anisotropy is a prerequisite for stable glass formation. Here we use PVD of tetrachloromethane, simple molecule nearly isotropic structure. In situ AC nanocalorimetry was characterize the vapor-deposited glasses. Glasses were produced by near 0.8 Tg. The isothermal transformation into supercooled liquid state gave further evidence tetrachloromethane forms...

Previous work has shown that vapor-deposition can prepare organic glasses with extremely high kinetic stabilities and other properties would be expected from liquid-cooled only after aging for thousands of years or more. However, recent reports have some molecules form vapor-deposited limited stability when prepared using conditions to yield a stable glass. In this work, we vapor deposit 2-ethyl-1-hexanol over wide range deposition rates test several hypotheses why molecule does not highly...

Acetonitrile thin films were prepared on Pt(111) and graphene using molecular beam techniques. Temperature programed desorption (TPD) experiments of acetonitrile displayed first-order kinetics for monolayer zero-order multilayer desorption. We used reflection adsorption infrared spectroscopy (RAIRS) to characterize the orientation Pt(111). molecules have been shown adopt a bridging structure where C≡N bond breaks form two single bonds underlying platinum atoms. When Tdeposition ≥ 120 K, our...

In situ AC nanocalorimetry was used to characterize vapor-deposited glasses of three phosphates with increasing lengths alkyl side chains: trimethyl phosphate, triethyl and tributyl phosphate. The as-deposited were assessed in terms their reversing heat capacity, onset temperature, isothermal transformation time. Glasses a range kinetic stabilities prepared, including kinetically stable glasses, as indicated by high temperatures long times. Trimethyl phosphate forms similar many other...

Crystalline acetonitrile has two polymorphs, a high-temperature (HT) phase that is stable between 217 K and its melting point at 229 low-temperature (LT) below K. Solid films can be prepared by vapor deposition in an ultrahigh vacuum chamber. To prevent sublimation of the film, temperatures are often kept 150 While LT thermodynamically favored these low temperatures, such preparation usually results formation metastable HT polymorph. In this work we use reflection adsorption infrared...

We measure the isothermal crystallization kinetics of amorphous acetonitrile films using molecular beam dosing and reflection adsorption infrared spectroscopy techniques. Experiments on a graphene covered Pt(111) substrate revealed that rate slows dramatically during long time periods overall cannot be described by simple application Avrami equation. The also have thickness dependence with thinner crystallizing much slower than thicker ones. Additional experiments showed decane layers at...