ABSTRACT
In this first chapter, we present a general introduction to the items that are at the basis of the book. We will give a fundamental description of materials and phenomena, referring to different approaches in literature, both experimental and theoretical, trying to link them among themselves and with the further aim of setting a non-ambiguous notation valid throughout the text. We will mainly concentrate on the aspects that will be discussed in the following chapters in order to provide a sort of glossary that can be consulted at any moment, starting from the very definition of glass.
