The Learning Center While there is no such thing as truly self-cleaning glass, there are surface treatments applied to the outside of the glass that can increase the time span between glass cleanings. This is made possible by a durable, transparent coating of titanium dioxide (TiO2) applied during the manufacturing process. The transparent coating is applied to hot glass during the forming process to form a strong, long-lasting bond, which makes the coating an integral part of the outer glass surface. This coating has photocatalytic properties that react chemically with the sun’s ultraviolet rays, causing dirt and other organic materials that are on the glass surface to slowly decompose and loosen. It works even on a cloudy day because a significant amount of ultraviolet radiation passes through cloud cover. There is even enough reflection radiation in shaded areas for this process to work nonstop throughout the day in all areas. The hydrophilic qualities of glass cause water droplets to spread out, or sheet, across the surface of the glass. When rain or a light spray of water hits the window, the water carries away the loosened dirt. This sheeting action also helps the window dry quickly with minimal spotting or streaking. Some companies even treat the surface with a thin layer of silicon dioxide which makes the surface exceptionally smooth, even more hydrophilic than normal hydrophilic glass. This super smooth surface allows water to disperse evenly or sheet off and evaporate quickly, greatly reducing water spotting. 7. What is self-cleaning or low maintenance glass? < back to list of questions about glass WINDOW GLASS 3245 Miracle Drive Murrysville, PA 15668 724-387-2991 PA Contractor ID PA001856