Glass-Transition Temperature of Polymers

Polymers that have a Tg greater than room temperature are in the glassy state at room temperature. These plastics tend to be hard and brittle at room temperature. For example, PVC is in the glassy state at room temperature but it can be easily modified to be rubbery by the addition of plasticizers.
The table below provides some of the glass transition temperatures of the polymers.

Source:
http://www.zeusinc.com

Factors affecting the Tg of a Polymer

The following factors are known to have influence on the glass transition temperature of a polymer

• Chain Length
• Plasticizers
• Chain stiffness and side groups
• Copolymers
• Pressure