Glass is considered cold at room temperature. Its composition does not begin to change until it reaches a temperature of between 700 and 900 degrees. At these temperatures, glass begins to have the consistency of a pudding setting up. Those who work with glass know it gets to a workable temperature at around 1250 degrees where, it has the consistency of taffy.
The process of cooling glass from these extremely high temperatures must be done slowly to reduce the risk of cracking or shattering the glass.Learn more about States of Matter