Photochromic compounds
US4342668A · kind A · utility
180Cited by
4References
9Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jul 28, 1980 |
| Grant date | Aug 3, 1982 |
| Priority date | — |
| Expiry date | Jul 28, 2000 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02C7/02
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
Photochromic compounds of the formula ##STR1## wherein one of R.sub.1 and R.sub.2 is halogen or lower alkoxy, and the other is hydrogen, R.sub.3 and R.sub.4 are hydrogen, lower alkyl, lower alkoxy, or halogen and R.sub.5 is an alkyl of 2 to 10 carbons, and their use in lenses are disclosed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.