Electron spin resonance in glasses

The present paper reviews a quarter of a century of electron spin resonance (ESR) studies in glasses. Specific subtopics addressed include transition-group ions, radiation-induced defect centers, ferromagnetic precipitates, and photo-induced centers. For brevity, most of the examples in the first three categories are confirmed to the familiar oxide glass systems and only the most concrete conclusions are elaborated. The section treating radiation-induced defects is further abridged in light of several reviews of this topic in the current literature. Even within these limitations of scope, a great diversity of material is summarized. Most of the studies cited provide information concerning the atomic scale structure of the host glasses and several have immediate impact on practical problems ranging from glass technology to geochemistry.