This paper reviews various factors impacting the thermal stability of fire-rated glass from both a chemical and physical perspective. The paper discusses the mechanisms of thermal expansion and contraction, scrutinizing the interplay between these mechanisms and the glass's structural integrity under high heat conditions. The process of glass softening, which can have critical consequences for the glass's fire-resistance, is also detailed, revealing how this phenomenon is controlled by the glass's chemical composition. Furthermore, the review explores how the glass's composition, including the types and proportions of additives, impacts its behavior in fire conditions. By compiling and analyzing these insights from across the scientific literature, the review contributes to a more complete understanding of the factors that govern the performance of fire-rated glass and provides a basis for the development of improved fire-resistant glass formulations.