COLLECTIVE DYNAMICAL ASPECT RELATED TO VITRIFICATION IN CONNECTION WITH STRUCTURAL CHARACTERIZATION

Structural characterization has been made for the same disordered mate rial in 3 different thermodynamic states: liquid, supercooled and glas sy. It concerns the aqueous electrolyte LiCl, 6H2O. Using isotopic sub stitution, we can analyse the pair distribution functions and precise the modifications induced by the glass transition and the melting in t he short, medium and long range order. Particularly interesting is the medium range order (between four and five angstrom), which appears mo re similar in the supercooled and glassy state than in the liquid stat e. On the basis of this structural analysis we will discuss the collec tive dynamical motion and the relaxational behavior. Because the inves tigated materials are aqueous solutions, comparison will be made with the H-bond characteristics.