What is Photochromism used for?

Photochromic materials can be used for the design of optical switches, optical data storage devices, energy-conserving coatings, eye-protection glasses, and privacy shields. Photochromic materials and systems have several important uses depending on the rates of the optical transformations.

What are photochromic properties?

Photochromic materials are those that show a reversible change in optical properties (color) through the action of light, i.e., electromagnetic radiation. They belong, therefore, to the chromogenic class of materials.

How do photochromic materials work?

How Do Photochromic Lenses Work? Tiny molecules of silver halide and chloride are embedded within a photochromic lens which is invisible and clear until exposed to sunlight/UV rays. A chemical process takes place when exposed to sunlight/UV and the molecules effectively move, change shape and absorb the light.

What are photochromic dyes?

Photochromic dyes generate dynamic reversible colour change under the sunlight or ultra violet (UV) light in the range of 300 to 360 nanometers. When placed into sunlight, or ultra violet rays, the molecular structure changes allowing the photochromic compound to turn into a darker colour.

What causes Photochromism?

Once UV light is exposed to the substance, the molecules react by ‘twisting’, creating an open form. This open form causes the Photochromic dye to turn into a colour. Once the UV light is removed, the molecules ‘twist’ back to their ‘flat’ state, reversing back to the colourless substance.

Is photochromic a coating?

WeeTect Photochromic Technology (WPT) includes two types of photochromic technologies. Once of them is photochromic coating. The substrate is injection molded polycarbonate lenses, polycarbonate visors or polycarbonate face shields. Then we use special photochromic material to do photochromic coating on the surface.

Can photochromic lenses be polarized?

Can photochromic lenses also be polarized? It isn’t very common, but lenses that are both photochromic and polarized exist. One example is the Transitions Vantage line of lenses. When these lenses darken in sunlight, they also become polarized.

How long does photochromic lenses last?

Photochromic lenses are worn for patients to see comfortably in any light. How long do photochromic lenses last? Photochromic lenses last as long as your prescription. Plastic photochromic lenses usually out last the lifetime of a patient’s prescription, about 2.5 years.

What do you call glasses that turn dark in the sun?

What are photochromic lenses? Photochromic or “adaptive” lenses darken when exposed to UV light, such as when you walk outdoors. When you are no longer exposed to the effects of UV, (i.e. walk indoors), the lenses return to their clear state.