Nuclear spin relaxation and atomic motion in inorganic glasses

Abstract

Results of temperature and frequency dependence of nuclear spin relaxation (NSR) are presented for different inorganic glasses between 0.4 K and the glass transition temperature. Below about 200 K, the data can be interpreted consistently in the framework of thermally activated low-frequency excitations of disordered modes. The modes are described by asymmetric double well potential (ADWP) configurations with suitable densities of states. Above about 200 K, the NSR is due to diffusive jumps of ions but deduction of corresponding transport properties (i.e. diffusion coefficients) from such data by means of standard NSR theories turns out to be difficult. Models are discussed which attempt to overcome these difficulties by relating the NSR with electrical conductivity. Further, deuterium NMR is shown to elucidate the motional mechanism of D 2O molecules and dynamical properties of the glass transition in electrolyte glasses.