NMR has been used very widely for the last 25 years to study the structures of glasses. Chemists and materials scientists need to understand how the structure and properties of glasses are related in order to improve the properties and processing of technologically useful glasses. Earth scientists use glasses as analogues for silicate melts because of the experimental difficulties associated with making spectroscopic and other measurements on molten silicates at extremely high temperatures. An array of different NMR experiments has been applied to glasses, and novel information has been obtained on structures and dynamic processes over a variety of length and time scales. It should be noted at the outset that glass structure represents the structure of a metastable melt at T_g, the glass transition temperature, i.e. usually several hundred degrees below the liquidus. The detailed information on glass structure available from NMR studies, especially where T_g is modified by changing the thermal history of the glass, must therefore be integrated with other spectroscopic and thermodynamic measurements of melts at high temperature to obtain the most complete understanding of silicate melt structure.

Several excellent reviews of the application of NMR to glasses have been published, e.g. Eckert (1992), MacKenzie & Smith (2002), Stebbins (1995a, 2001), Zwanziger (1998), and the subject is now far too large to be covered comprehensively in a single review paper. In this contribution I will therefore only discuss the structures and properties of silicate glasses, and will focus on a few key examples of the type of information which is now available.