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What happens to the atoms when a glass-forming liquid cools without crystallizing?

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When a glass-forming liquid cools without crystallizing, it undergoes a process known as the glass transition rather than freezing into a regular, periodic structure.1

As the liquid cools, its viscosity rises significantly, and the rate of molecular movement slows down. When the material reaches the glass transition temperature ( $T_{g}$ ), the response time for molecular rearrangement becomes much longer than the time available during the cooling process. Consequently, the liquidlike mobility disappears, and the atoms become "frozen" into a set of fixed positions.21

Unlike crystalline solids, which exhibit long-range order, the resulting amorphous solid lacks translational periodicity. However, the atoms are not randomly distributed; they maintain short-range order due to the chemical bonding between them. In many oxide glasses, this results in a continuous random-network of polyhedra, such as SiO $_{4}$ tetrahedra, which are connected at their corners but lack a repeating pattern.134