If crystallization is avoided while cooling a liquid, it will become a supercooled liquid and eventually a glass at Tg. Creating glasses that are lower on the energy landscape can not only help us understand the glass transition but are also of technological importance. Two traditional ways of gaining additional stability in glasses is to lower the rate of cooling or to age a glass for many days or even months below Tg. We show that vapor depositing indomethacin or 1,3-bis-(1-naphthyl)-5-(2-naphthyl)benzene can create glasses with remarkable kinetic and energetic stability in far less time than traditional methods. The stability of these organic glasses can be controlled by the temperature of the substrate during deposition and the deposition rate; glasses deposited near Tg-50 K and at the slowest rates show the greatest stability. Preliminary x-ray measurements also show that glasses prepared by vapor deposition exhibit additional order as compared to samples cooled from the melt. These results are explained by an enhanced surface layer mechanism where the top few nanometers of the film are much more mobile as compared to the bulk.
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