Photochromatic Sunglasses

How does the photo chromischen glasses work? Here you will find the answer. It’s called Photochromatic sunglasses sunglasses and prescription glasses which darken automatically as soon as they are exposed to the Sun. These special glasses have been developed around 1960 by Corning and in 1990 made by the company of transitions. Photochromatic sunglasses develop a chemical reaction as soon as the lens with UV rays in contact. The glass is composed of millions of molecules and substances such as bleach or silver silver halide. nthal. The molecules are transparent to visible light in the absence of UV light. As soon as the molecules with the UV rays in touch they undergo a chemical process and changed the shape of the molecule.

The new molecular structure absorbed parts of visible light, so that automatically darkens the sunglasses. The number of molecules that change their shape varies with the intensity of UV rays. If you are for example indoors and expose no UV rays are, is a reversal of the chemical Process instead. The sudden absence of UV forces radiation back to the original form back to change the molecules, meaning that is the darkening of the glass. The Brown and grey lenses created by Corning were made of glass and the molecules were evenly distributed over the whole lens. The problem with this method was, as soon as it has been applied in prescription lenses, the thicker glass bodies were often darker than the less thick. Nowadays, fewer lenses are made of glass, but you can find sunglasses with highly developed plastic glasses.

A method was developed, which makes plastic lenses perfectly and evenly photo chromisch. Immerse the plastic lenses in a chemical bath, absorb the fotochromen molecules at a depth of about 150 micrometres in the plastic. This turned out to be much better than a simple coating, which is only about 5 micrometers thick and generated enough molecules, enough to make dark lenses.