How Photochromic Technology Works

The glass is made from a special photochromic glass that contains about 0.01% to 0.1% silver halide crystals. These crystals are transparent and so small that they leave the glass almost perfectly clear. But when the glasses are exposed to birght sunlight, which contains substantial amounts of ultraviolet light, the silver ions in those crystals are reduced to silver atoms and begin to form tiny silver particles inside the glass. Like the particles that form in black and white photography, these silver particles are so jagged and imperfect that they're light absorbing rather than shiny. The glasses thus darkens when exposed to sulight. But when the glasses are returned to the dark, the halogen gas atoms recombine with the silver atoms and reform the silver halide crystals. The glass once again becomes clear.

Basically, photochromic glass uses silver halide crystal techology to adjust the density of their tint to varying light conditions. Bright conditions will cause the glass to darken. Lower light will allow the glass to lighten. Photochromic features give the advantage of added versatility in a glass.

One of the most recent changes in the area of photochromic glass has been the use of anti-reflective (A-R) coating as an enhancement.

           How Sun Shield Works With the Sun

           How Sun Shield Works Without the Sun