Molecular dynamics of ethylene glycol adsorbed in NaX:: NMR and broadband dielectric spectroscopy studies

Proton spin relaxation and broadband dielectric spectroscopy are applied to study the dynamics of ethylene glycol adsorbed in NaX, EG/NaX. The molecular mobility strongly depends on the pore filling factor which may be controlled by high-resolution H-1 MAS NMR measurements. Although EG in bulk shows a Vogel-Fulcher-Tammann type of activation, temperature dependent relaxation rate measurements for the EG/NaX systems always follow an Arrhenius plot, independent of the loading degree. There is no hint to a glass-forming behaviour of EG/NaX which could be understood in terms of the strong influence of surface-molecule interactions playing a dominant role compared to the molecule-molecule interactions. (c) 2005 Elsevier B.V. All rights reserved.