The glass transition point, also known as the glass transition temperature (Tg), is the temperature at which an amorphous polymer undergoes a transition from a rigid, glassy state to a rubbery, viscous state. This transition is accompanied by a significant change in the polymer’s mechanical properties, such as modulus, hardness, and coefficient of thermal expansion. The glass transition temperature is crucial in determining the temperature range over which a polymer behaves as a rigid solid or a flexible material and influences its suitability for various applications, including processing conditions, storage stability, and end-use performance.