The glass is an inorganic material that is melted at a high temperature (800 degrees or more, and the daily glass is generally melted at 1100 degrees). Below the softening point temperature, no chemical change occurs. Above the softening point temperature, it just softens, melts or decomposes, and there is no burning phenomenon.

Glass fiber cloth is made by drawing glass into a very fine glass fiber, and the glass fiber at this time has good flexibility. The glass fiber is spun into a yarn, which can then be woven into a fiberglass cloth by a looms. Since the glass filament is extremely thin and the surface area per unit mass is extremely large, the temperature resistance is lowered. It is like melting a thin copper wire with a candle.