Photochromic compounds

US6936725B2 · kind B2 · utility

Assignee

• RODENSTOCK GMBH · DE

Inventors

• Manfred Melzig · Weßling, DE
• Herbert Zinner · Pentling, DE

Key dates

• Filing date: Mar 29, 2001
• Grant date: Aug 30, 2005
• Expiry date: Jun 11, 2023

Classification

• Technology area (CPC G): Physics
• CPC primary: G03C1/73
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

A photochromic compound suitable for use as a single substance for photochromic tinting of a transparent plastic article so that the tinted article has a neutral gray or brown color in the excited state, is made by fusing at least two non-identical photochromic sections to an aromatic structure. The photochromic sections are selected so that the different absorption wavelengths of the excited photochromic sections give rise to a neutral gray or brown color in the plastic material and are selected from the group consisting of oxazines and pyrans. At least one of the photochromic sections is not an indolino spiropyran. The aromatic structure to which the photochromic sections are fused is selected from the group consisting of benzene, biphenyl, naphthalene, anthracene and phenanthrene. The positions of fusion of the photochromic sections on the aromatic structure are directly adjacent to the oxygen atom of the pyran or the oxygen or nitrogen atom of the oxazine.