Patent ID: 7101497

Claim:
A photochromic material, comprising: one or more illuminants which emits a light when irradiated with radiation, one or more diarylethene compounds, wherein the diarylethene compound is represented by the following formula (0), and the absorption spectrum of the ring opened form of the diarylethene compound, and the emission spectrum of the illuminant, overlap each other: wherein formula (0), each of the groups R 1 and R 2 which are independent of each other, is an alkyl group, a cycloalkyl group or an alkoxy group, each of groups X 1 , X 2 , Y 1 and Y 2 which are independent of one another, is one of the group R 3 is a hydrogen atom, an alkyl group which may be substituted, an aryl group which may be substituted, or a cycloalkyl group which may be substituted, the group R 4 is a hydrogen atom, an alkyl group which may be substituted, or a cycloalkyl group which may be substituted, the ring D 1 is a 5- or 6-membered aromatic ring which is formed by groups X 1 and Y 1 together with two carbon atoms bonded thereto and which may be substituted, and the ring E 1 is a 5- or 6-membered aromatic ring which is formed by groups X 2 and Y 2 together with two carbon atoms bonded thereto and which may be substituted, the rings D 1 and E 1 may further have a 5- or 6-membered aromatic ring which may be substituted, condensed thereto; and one or more ultraviolet absorbers.