Glass Transition Temperature of Polymers

High-molecular-weight amorphous polymers undergo a change from a glassy to a rubbery state on heating. Conversely, it changes from a rubbery to a glassy state on cooling. This is called glass transition, which occurs at glass transition temperature (T_g). But low-molecular-weight polymers change from a glassy to a liquid state above the flow temperature. Glass transition is important in many fields such as food processing, functioning of vibration dampers, and polymer electrolytes. Glass transition of a polymer is so crucial that sometimes it can defeat a great mission that aims at the progress of entire mankind. In addition, at times, it can even take the lives of many people as in a space shuttle, such as the Challenger disaster.