Silicon dioxide plays a central role in most contemporary electronic and photonic technologies, from fiber optics for communications and medical applications to metal-oxide-semiconductor devices. Many of these applications directly involve point defects, which can either be introduced during the manufacturing process or by exposure to ionizing radiation. They can also be deliberately created to exploit new technologies. This book provides a general description of the influence that point defects have on the global properties of the bulk material and their spectroscopic characterization through ESR and optical spectroscopy.Proceedings of the NATO Advanced Study Institute, Erice, Italy, April 8-20, 2000Silicon dioxide plays a central role in most contemporary electronic and photonic technologies, from fiber optics for communications and medical applications to metal-oxide-semiconductor devices. Many of these applications directly involve point defects, which can either be introduced during the manufacturing process or by exposure to ionizing radiation. They can also be deliberately created to exploit new technologies. This book provides a general description of the influence that point defects have on the global properties of the bulk material and their spectroscopic characterization through ESR and optical spectroscopy.Preface. Structure and Topology. Defect-free vitreous networks: The idealised structure of SiO2 and related glasses; A.C. Wright. Topology and topological disorder in silica; L.W. Hobbs, X. Yuan. Bulk Defects. Optical properties of defects in silica; L. Skuja. The natures of point defects in amorphous silicon dioxide; D.L. Griscom. Ab initio theory of point defects in SiO2; G. Pacchioni. A demi-century of magnetic defects in alpha-quartz; J.A. Weil. Interaction of SiO2 glasses with high energy ion beams and vacuum UV excimer laser pulses; H. Hosono, K. Kawamura. Excitons, localized states in silicon l#