Nucleation and medium Range Order in Silicate Liquids: Inferences From NMR Spectroscopy

Abstract

ABSTRACTNMR spectroscopy is beginning to provide quantitative information on short- and medium-range structure in silicate glasses and liquids, and on molecular-scale dynamics in the liquids. Data on coordination numbers, second and higher neighbor connectivities, and larger scale heterogeneities, as determined by NMR at ambient and high temperatures, are potentially very useful in models of nucleation and growth of immiscible liquid and crystalline phases. New techniques such as dynamic angle spinning (DAS), high temperature magic angle spinning (MAS) are especially promising. Detailed studies of paramagnetic nuclear spin relaxation can characterize compositional heterogeneity in glasses to distance scales of at least several nanometers.