vitrified

Vitrified is an adjective describing a substance that has been transformed into a glass-like, non-crystalline solid by heat. The term comes from Latin vitrificare (“to make glass”), from vitrum “glass.” In materials science, vitrification implies a transition to a glassy state, often yielding a dense, impermeable microstructure.

In ceramics, vitrification refers to the densification of a ceramic body during firing as a glassy phase forms within the matrix. A vitrified ceramic typically has low porosity and high strength. Porcelain and other vitrified tiles are designed to reach a high degree of vitrification, yielding very low water absorption and increased durability. The degree of vitrification is commonly described by porosity or water absorption measurements; products are marketed as vitrified, fully vitrified, or semi-vitrified depending on the firing.

In archaeology, vitrified fortifications describe structures in which interior materials were exposed to intense heat, fusing stone or timber into a glass-like slag. The interpretation of such vitrification is debated, with explanations ranging from deliberate burning to natural or accidental processes. In waste management, vitrification also refers to immobilizing hazardous or radioactive waste by incorporating it into borosilicate glass, producing a stable, durable waste form.

In glassmaking, vitrification describes the fundamental process of melting silica with fluxes to form glass; the resulting product is amorphous and lacks long-range crystalline order.