RAMAN-SPECTRA OF CS5H3(SO4)(4)CENTER-DOT-H2O CRYSTALS IN THE PROTON GLASS STATE

Polarized Raman spectra of Cs5H3(SO4)(4) . H2O (PCHS) single crystals were measured in the frequency range 0-4000 cm(-1) at 20-300 K, i.e. b oth below and above the glass transition temperature (T-g). The evolut ion of the spectra with decreasing temperature indicates that the orie ntational disorder of SO42- ions and H2O molecules changes at T-g from the dynamical to a static one. A scenario for the glass transition an d a model of the resulting glass state is suggested. in which the wate r molecules (H bonds) play the role of binding constituents of the iso lated sulphate complexes H-3(SO4)(4)(5-).