This book brings together many different relaxation phenomena in liquids under a common umbrella and provides a unified view of apparently diverse phenomena. It aligns recent experimental results obtained with modern techniques with recent theoretical developments. Such close interaction between experiment and theory in this area goes back to the works of Einstein, Smoluchowski, Kramers' and de Gennes. Development of ultrafast laser spectroscopy recently allowed study of various relaxation processes directly in the time domain, with time scales going down to picosecond (ps) and femtosecond (fs) time scales. This was a remarkable advance because many of the fundamental chemical processes occur precisely in this range and was inaccessible before the 1980s. Since then, an enormous wealth of information has been generated by many groups around the world, who have discovered many interesting phenomena that has fueled further growth in this field. As emphasized throughout the book, the seemingly different phenomena studied in this area are often closely related at a fundamental level. Biman Bagchi explains why relatively small although fairly sophisticated theoretical tools have been successful in explaining a wealth of experimental data at a semi-phenomenological level.

With the development of lasers that can generate light 11 14 pulses ranging from 10- - 10- sec duration, and capable of 13 peak powers in excess of 10 watts scientists have been able to investigate the interactions of light with matter in a time and power domain not previously possible. These ultrashort laser pulses provide a powerful tool for the study of chemical phenomena at the most fundamental level. Many of the elementary processes of importance in chemistry including energy dissipa tion, molecular motions, structural and chemical changes occur on a very short time scale and thus require special approaches. Th~ use of ultrashort laser pulses to perturb and to probe systems of interest affords a direct approach to the time reso lution of very rapid chemical phenomena. It was recognition of the impact of these relatively new approaches to chemical phenomena that motivated NATO to sponsor a meeting on the applications of picosecond spectroscopy in chemistry. The primary aim of the NATO workshop was to gain some perspective on the status of the field in terms of present research activities, technological developments and if possible the difficult task of sensing future directions. The way we decided to approach these issues was to gather together the main contributors to the field, fortunately many of whom were able to attend, to present their work and to participate in what turned out to be lively discussions of the field.

This Encyclopedia begins with an introduction summarizing itsscope and content. Glassmaking; Structure of Glass, GlassPhysics,Transport Properties, Chemistry of Glass, Glass and Light,Inorganic Glass Families, Organic Glasses, Glass and theEnvironment, Historical and Economical Aspect of Glassmaking,History of Glass, Glass and Art, and outlinepossible newdevelopments and uses as presented by the best known people in thefield (C.A. Angell, for example). Sections and chapters arearranged in a logical order to ensure overall consistency and avoiduseless repetitions. All sections are introduced by a briefintroduction and attractive illustration. Newly investigatedtopics will be addresses, with the goal of ensuring that thisEncyclopedia remains a reference work for years to come.