Details

Autor(en) / Beteiligte

• Dalal, Shakeel S
• Ediger, M. D

Titel

Molecular Orientation in Stable Glasses of Indomethacin

Ist Teil von

• The journal of physical chemistry letters, 2012-05, Vol.3 (10), p.1229-1233

Ort / Verlag

United States: American Chemical Society

Erscheinungsjahr

2012

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Spectroscopic ellipsometry has been used to measure the properties of indomethacin prepared by physical vapor deposition at T substrate/T g = 0.78, 0.84, and 0.90. The as-deposited glasses exhibited high kinetic stability and had densities 0.8–1.2% higher than the ordinary glass prepared by cooling the liquid at 1 K/min. Deposition at the higher temperatures yielded glasses with positive birefringence (up to Δn = 0.028), while the lowest-temperature sample was negatively birefringent (Δn = −0.015). These results indicate that substrate temperature can be used to manipulate molecular orientation in high-density and high-stability glasses. The data for the supercooled liquid and the ordinary glass of indomethacin are reasonably consistent with the Lorentz–Lorenz equation, but significant deviations are noted with the as-deposited materials.