polymer glass transition

The polymer glass transition is the process where a polymer material changes from a hard, brittle solid (glassy state) to a softer, more flexible one (rubbery state) as temperature increases. Below this temperature, the molecular chains are mostly frozen in place, leading to rigidity. When heated past the transition temperature, these chains gain enough mobility to slide past each other, making the material less stiff and more elastic. This shift isn't a true melting but a gradual change in physical properties, crucial for applications like plastics and rubber where temperature control affects performance.