Tinted glass achieves its performance by absorbing solar energy and so is sometimes referred to as heat absorbing glass. This heat absorbing quality means the glass is thermally stressed so some thicker or darker products may need to be toughened (chemically treated) to avoid thermal stress breakage. Toughened glass is a type of safety glass processed by controlled thermal or chemical treatments to increase its strength compared with normal glass. Chemically strengthened glass is typically six to eight times the strength of float glass; this makes it ideal for panoramic roofs. Tinted float glass can be processed into heat strengthened, toughened, laminated, and curved glass. Tinted glass products are sourced from quality float glass manufacturers including Guardian, Glaverbel, Asahi and Pilkington.
Grey float glass is the traditional medium grey tinted glass characterized by its low light transmission and good control of solar heat and glare. This glass is manufactured in thicknesses ranging from 4 - 12mm.
The roofs of some cars with panoramic glass, like Kia Optima, for example, are painted in dark reflective colours or covered with materials designers call foils to give the impression of a roof made entirely of glass.