PHOTOCHROMIC BIS-NAPHTHOPYRAN COMPOUNDS AND METHODS FOR THEIR MANUFACTURE

摘要

The invention provides photochromic bis-naphthopyran compounds of formula (I ), as well as methods for their manufacture and their use. The bis-naphthopyran compounds of the invention exhibit a wide range of color, i.e., from pink to purple to blue gray, upon activation by a source of UV light. Additionally, the bis-naphthopyran compounds of the present invention exhibit broad coloration ability, fast response as to both color change on activation and return to original color, and good fatigue-resistance.