| 摘要 |
A series of photochromic compounds are disclosed which have the property of undergoing a reversible colour change when exposed to unfiltered sunlight and reverting to their original colour in the absence of U.V. light at room temperature. These compounds have the general formula:- <CHEM> Ad@C &ldurule& represents an adamantylidene or a substituted adamantylidene group; R1 represents hydrogen, alkyl, aryl, aralkyl or a heterocyclic group, X represents oxygen or > NR2, in which R2 is hydrogen, aryl, alkyl or aralkyl and <CHEM> represents and aromatic group, an unsaturated heterocyclic group or a benzannelated heterocyclic group. The photochromic compounds of the invention are useful in the manufacture of photoreactive lenses, particularly plastic lenses. |
