Photochromatic composition and photochromatic articles which contain it
US5180524A · kind A · utility
33Cited by
1References
13Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Feb 4, 1991 |
| Grant date | Jan 19, 1993 |
| Priority date | — |
| Expiry date | Feb 4, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03C1/685
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A photochromatic composition contains at least two photochromatic compounds, defined by the general formula: ##STR1## wherein the various substituents from R.sub.1 to R.sub.7 and X are as defined in the specification. In such a mixture, at least one photochromatic compound is defined by the general formula, wherein R.sub.7 represents a hydrogen atom, and at least one further compound is also defined by the general formula, wherein R.sub.7 represents an -NR.sub.8 R.sub.9, with R.sub.8 and R.sub.9 having the meaning as defined in the text.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.