The flows in glassy materials are stopped by a process called vitrification. Vitrification occurs when a liquid is cooled so rapidly that its atoms or molecules do not have time to arrange themselves into a crystalline structure. Instead, they form a rigid, non-crystalline structure that is characteristic of glass.

The rate of cooling required for vitrification depends on the composition of the liquid. Some liquids, such as silica, require very rapid cooling to prevent crystallization. Others, such as metallic alloys, can be cooled more slowly.

Vitrification is an important process in the production of glass. By controlling the cooling rate of a liquid, manufacturers can create glasses with different properties. For example, glasses that are cooled very rapidly are more likely to be transparent, while glasses that are cooled more slowly are more likely to be opaque.

Vitrification is also used in other applications, such as the preservation of food and the production of medicines. In the food industry, vitrification is used to freeze-dry food products, which removes water from the food without damaging its structure. In the pharmaceutical industry, vitrification is used to preserve vaccines and other medicines that are sensitive to heat or light.