DYNAMIC EVIDENCE OF CHEMICAL AND PHYSICAL TRAPS IN H-BONDED CONFINED LIQUIDS

Rayleigh wing, infrared (IR) absorption, and Raman-scattering measurem ents are employed to investigate the reorientational and vibrational d ynamics of ethylene glycol and its homologous systems, namely ethylene glycol monomethyl ether and ethylene glycol dimethyl ether, in the bu lk state and confined into 25 Angstrom pores of a sol-gel porous glass . As far as the Rayleigh wing data are concerned, the quantitative ana lysis of the different contributions in the spectra shows the clear in fluence of the physical and chemical confinement on the mobility of th e studied liquids. In addition the IR and Raman measurements, performe d in the O-H stretching region, allowed to identify the intramolecular , II-bond imposed, sub-band, as well as to connect the various sub-ban ds to different intermolecular environments originated by the existenc e of the II-bond potential. The observed dynamics is discussed on the basis of current theories for associated liquids. (C) 1998 American In stitute of Physics. [S0021-9606(98)52041-7].