Chemistry

[Edgley Gonzaga]

What's the chemistry of the transition lenses? How does it work???

Thanks

[Jim Schafer]

Hello Edgely,

Photochromic lenses are a chemical reaction. The main family of photochromics in Transitions Lenses are napthopyrans.

If you wish, you can go to transitions.com and read up on our products and technology in Brasilian Portuguese.

In the short form, only the front surface of a Transitions lens is photochromic, sunlight (UV and Visible Light Spectrum) supply the energy to start and feed the chemical reaction. By having the photochromics on the front surface, the activation will always be even, no matter the lens configuartion or design. It will also be the clearest product indoors.

Here is a quick refresher for everyone, a closed molecule is clear (or a chosen color), an open molecule is colored. Light, and in our case UV Light causes the molecule to swell, split open and absorb color in the Visible Spectrum. This is happening lightening fast and constant the whole time the molecules see daylight. Once removed from the energy source (daylight) the uv source is gone and the molecules stay closed and in the chosen state of clear or color.

Because there are millions of molecules in the surface of that lens, a too loose of a substrate would not react near as fast to changing light conditions. In theory, until the UV energy was consumed by the molecules, a lens would keep darkening if you went from full sun to indoors. By having the proper matrix match with the compounds the reaction can be very crisp and tight. The other thing that can happen is the molecules react so fast the color is muted or washed out looking. You need that balance of molecules in a closed and open state.

I hope this helps,
regards,
Jim

[Edgley Gonzaga]

Hi Jim

You were quiet clear in your explainnation, thanks. Now I got a little confused about these names:

Idolino Spronaphthoxazines,
Oxazines
Naphthopyran
Fulgide derivatives

Also I would like to know about how the UV make the change..

Thanks for the helping hand

Edgley