Amorphous polymers are polymeric materials whose molecular chains are randomly entangled and lack a regular, long-range crystalline order. Because of this disordered structure, these materials do not exhibit a distinct melting point; instead, they undergo a characteristic glass transition across a specific temperature range. Below their glass transition temperature, amorphous polymers are typically rigid, hard, and brittle, whereas above this temperature, molecular mobility increases and the material transitions into a flexible, rubbery, or viscous state. The absence of crystalline domains that scatter light frequently makes pure amorphous polymers optically transparent, with common examples including polystyrene, polycarbonate, and poly(methyl methacrylate).
