The most common plastic materials used for commercial glazing products are polycarbonate, acrylic, glass-reinforced polyester, and polyvinyl chloride (PVC). Plastics can be as optically transparent as glass, but are considerably more flexible than glass, which leads to plastics' shatter-resistant properties. When plastics do shatter, they tend to break into large, dull-edged pieces, rather than the smaller, sharper fragments typical of glass.
Many plastic glazing materials have only half the specific gravity of glass, giving them a decided weight advantage. However, plastics have a much higher coefficient of thermal expansion than glass, which can present design challenges when tight spaces between glazing and adjacent surfaces are desired. Within the plastic glazing family there are wide differences in impact strength. In general, polycarbonate and glass-reinforced polyester are far more impact-resistant than acrylic or PVC. Plastic glazing is more easily scratched than glass. However, various coatings, such as polysiloxanes, can make plastic glazing more scratch-resistant.