WINDOW TECHNOLOGIES: Advanced
Photochromic materials change their transparency in response to light intensity. Photochromic materials have been used in eyeglasses that change from clear in the dim indoor light to dark in the bright outdoors. Photochromics may be useful in conjunction with daylighting, allowing just enough light through for lighting purposes, while cutting out excess sunlight that creates glare and overloads the cooling system. Although small units have been produced in volume as a consumer product, cost-effective, large, durable glazings for windows are not yet commercially available.