Supercooled liquid

A supercooled liquid is a liquid cooled below its normal melting point without undergoing crystallization. It exists in a metastable state where the thermodynamic driving force for crystallization is present but the kinetic barrier—slow nucleation or limited atomic mobility—prevents the phase transition. Supercooled liquids are the raw material of the glass transition: when cooled further, they either crystallize abruptly or fall out of equilibrium and become glasses.

The study of supercooled liquids is central to understanding the Kauzmann paradox, because it is in the supercooled regime that the configurational entropy appears to approach zero. The depth of supercooling a liquid can sustain before crystallizing depends on its homogeneous nucleation rate and its critical cooling rate.