2H-NMR studies of supercooled and glassy aspirin

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Date

2007

Journal Title

Journal ISSN

Volume Title

Publisher

Elsevier

Abstract

Acetyl salicylic acid, deuterated at the methyl group, was investigated using 2H NMR in its supercooled and glassy states. Just above the glass transition temperature the molecular reorientations, studied using stimulated-echo spectroscopy, demonstrated a large degree of similarity with other glass formers. Deep in the glassy phase the NMR spectra look similar to those reported for the crystal and below 20 K they are indicating that rotational tunneling plays a role. Measurements of the spin-lattice relaxation times for temperatures below 150 K reveal a broad distribution of correlation times in the glass. The dominant energy barrier characterizing the slow-down of the methyl group motion is significantly lower than the well-defined barrier in the crystal.

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Table of contents

Keywords

Glass transition, Nuclear magnetic (and quadrupole) resonance

Citation

Nath, R.; Geil, B.; Nowaczyk, A.; Böhmer, R.: 2H-NMR studies of supercooled and glassy aspirin. In: Journal of Non-Crystalline Solids Nr. 41-43, Jg. 353(2007), S. 3788-3795, doi: 10.1016/j.jnoncrysol.2007.05.180.