abstract |
The present invention relates to photochromic [3H]naphtho[2,1-b]pyran compounds containing an acetylenic substituent, process for their manufacture, and photochromic materials and articles obtained therefrom. The invention, in some specific aspects, relates to photochromic compounds having a [3H]naphtho-[2,1-b]pyran structure and bearing an acetylenic group in one of the positions 7 to 10 of the naphthopyran ring structure. |