J. Phys. IV France
Volume 10, Numéro PR7, May 2000
International Workshop on Dynamics in Confinement
Page(s) Pr7-299 - Pr7-303
International Workshop on Dynamics in Confinement

J. Phys. IV France 10 (2000) Pr7-299-Pr7-303

DOI: 10.1051/jp4:2000760

Dynamics NMR investigations of a glassy crystal confined in porous materials

R. Decressain, E. Cochin and L. Carpentier

Laboratoire de Dynamique et Structures des Matériaux Moléculaires, UPRESA 8024 du CNRS, Université de Lille 1, 59655 Villeneuve-d'Ascq cedex, France

The temperature dependence of the proton relaxation rates has ben studied in molecular glassy crystals cyano-adamantane (C10H15CN) confined in the porous space of a silica glass of 60Å and 150Å nominal pore sizes. In the temperature range corresponding to the bulk plastic phase, the NMR proton lineshape of the confined materials revealed a two phase system consisting of a liquid-like component and a crystalline solid bulk-like component. As for the bulk, the [Math] process, related to the dipolar axis motion, controlled both T1z and T1p in the largest pores. From the NMR results we concluded that the dynamics of this [Math]-relaxation process is slightly enhanced by the confinement giving rise to a negative shift of the glass transition temperature. On the contrary, the confinement has no influence on the relaxation rates in the glassy state.

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