English to Polish Science Physics optics

The activation reaction begins when UV light enters into contact with the lens. The lens gradually gets darker until a maximum degree is reached: the lens is activated. The deactivation process occurs when the influence of the UV rays is removed, i.e. the colour gradually disappears until the original tone is obtained. Reversibility is often lost over time. This is called “fatigue”. However, photochromic lenses have been developed in recent years that are not prone to fatigue.

Activation affects the transmittance factor, but not reflection. In other words, the substrate reflects the same percentage of light, but greatly increases absorption in detriment of transmittance.