Silicate Glasses

Silicate glasses are important cultural, societal, and geological materials. Geologic glasses testify to the igneous activity of the Earth, and represent an important source of tools and ornamental objects during the Paleolithic. Nowadays, silicate glasses are used to make technical materials, such as smartphone screens or glass matrix for stabilizing hazardous radioactive wastes. Therefore, silicate glasses are central to the history of the Earth and humanity. The compositional landscape of natural and industrial silicate glasses is vast, with various elements that all affect the glass properties and structure differently. The SiO₄ tetrahedral framework, the backbone of silicate glasses, is variously modified by the introduction of network modifier metal cations or network former aluminum cations. Industrial and geologic silicate glasses further contain multivalent elements (e. g., Fe^2+/3+), rare-earth elements, and volatile elements (H, C, S, Cl, F, I) that play different roles in the glass structure and properties. This chapter proposes to review the links between the structure, the properties, and the chemical composition of silicate glasses.