Plastic Photochromic Lenses

Spirooxazines (NISO) have UV activation properties and thermal bleaching properties that are convenient for eyewear applications. A plastic photochromic lens must have several features, such as (1) ultraviolet energy protection, (2) comfortably lightweight, and (3) tint from a fashionably light tint to a functionally darker tinted sun lens. 45 

In the early 1980s, American Optical (AO) commercialized a NISO photo-chromic lens. However, the lens was unsuccessful in the market because of its hue when activated and poor response. 

---

As with most photochromic lenses, the performance of plastic photochromic lenses is temperature-dependent. In addition to variable light attenuation, photochromic lenses offer protection against UV light. Photochromic plastics coated onto classical glass lenses provide abrasion/scratch resistance and highly functional antireflectivity. For further details, the reader is referred to a review article [61]. 

J. Crano, Achieving the balance, plastic photochromic lens composition and fabrication, Frames Magazine, 8-10 (July 1996). 

---