Introduction

Abstract

Over the course of time, the concept “glass” has had various meanings. It can signify a certain condition of a substance (vitreous), a material (e.g., window glass), or an object (e.g., a wine glass). Thus, it is quite understandable that many definitions are found in print which to some extent differ greatly from one another. (The commonly used terms found in the German language are standardized [1145]. Additional help is provided by a dictionary published by the International Commission on Glass [435].) Practical considerations come into play as well. Scientists are satisfied if they can just obtain trace amounts in vitreous form, while glass makers designate a substance as glass-forming only when they are successful in making larger pieces of it in vitreous form. The next chapter will thus begin with questions of definition arising from such problems.