Title | Physical vapor deposition as a route to hidden amorphous states |
Publication Type | Journal Article |
Year of Publication | 2009 |
Authors | Dawson, K. J., K. L. Kearns, L. Yu, W. Steffen, and M. D. Ediger |
Journal | Proceedings of the National Academy of Sciences of the United States of America |
Volume | 106 |
Pagination | 15165-15170 |
ISBN Number | 0027-8424 |
Accession Number | WOS:000269632400016 |
Keywords | DYNAMICS, ENERGY LANDSCAPE, entropy, FREE-VOLUME, glass, GLASS-FORMING LIQUIDS, INDOMETHACIN POLYMORPHS, liquid-liquid transition, PHASE, POLYMER MELTS, SUPERCOOLED, SUPERCOOLED LIQUIDS, TEMPERATURE, TRANSITION, X-ray scattering |
Abstract | Stable glasses of indomethacin (IMC) were prepared by using physical vapor deposition. Wide-angle X-ray scattering measurements were performed to characterize the average local structure. IMC glasses prepared at a substrate temperature of 0.84 T(g) (where T(g) is the glass transition temperature) and a deposition rate of 0.2 nm/s show a broad, high-intensity peak at low q values that is not present in the supercooled liquid or melt-quenched glasses. When annealed slightly above T(g), the new WAXS pattern transforms into the melt-quenched glass pattern, but only after very long annealing times. For a series of samples prepared at the lowest deposition rate, the new local packing arrangement is present only for deposition temperatures below T(g) - 20 K, suggesting an underlying first-order liquid-to-liquid phase transition. |
DOI | 10.1073/pnas.0901469106 |
Alternate Journal | Proc. Natl. Acad. Sci. U. S. A. |