Photochromic compound and curable composition containing the photochromic compound

A photochromic compound represented by Formula (1) below comprising at least two of monovalent photochromic basic structural groups PC, the monovalent photochromic basic structural group including a T-type photochromic moiety and being bonded to an organic group having a non-SO aromatic ring containing neither a sulfur atom nor an oxygen atom,

• where m is an integer of 2 to 6,
• PC is the monovalent photochromic basic structural group,
• provided that at least one of L and R3 contains the non-SO aromatic ring,
• L is a phenylene group or a direct bonding,
• R3 is an m-valent organic group or a direct bonding, and
• when R3 is a direct bonding, m is two and L is a divalent organic group containing the non-SO aromatic ring,
• wherein the m-valent organic group R3 is selected from the group consisting of a saturated or unsaturated hydrocarbon group having 1 to 15 carbon atoms;
• a saturated or unsaturated aliphatic ring group that has 3 to 20 carbon atoms and may have a heteroatom in the aliphatic ring;
• a polyvalent silylene group that has 1 to 3 silicon atoms and has, as a substituent, at least one selected from an alkyl group having 1 to 15 carbon atoms, an alkoxy group having 1 to 15 carbon atoms, or a non-SO aromatic ring group having 6 to 30 carbon atoms;
• and an oxygen atom or a sulfur atom when m=2;
• or a carbon atom when m=4,
• wherein an organic group including the group R3 bonded to the PC has a molecular weight per PC of less than 300, and
• wherein each monovalent photochromic basic structural group PC is represented by Formula (2) below:
• where a is an integer of 0 to 4,
• b is an integer of 0 to 4,
• R4 and R5 are each the following group:
• a hydroxyl group;
• an alkyl group;
• a cycloalkyl group;
• an alkoxy group;
• an amino group;
• a cyano group;
• a halogen atom;
• a nitro group;
• a formyl group;
• a hydroxycarbonyl group;
• an alkylcarbonyl group;
• an alkoxycarbonyl group;
• an aryl group;
• a heterocyclic group;
• an alkylthio group;
• a cycloalkylthio group;
• an arylthio group;
• an aralkyl group;
• an aralkoxy group;
• an aryloxy group;
• a thiol group;
• an alkoxyalkylthio group;
• a group represented by Formula (X) below:
• where E is an oxygen atom or NR101 where R101 is a hydrogen atom or an alkyl group,
• F is an oxygen atom or a sulfur atom,
• R201 is a hydrogen atom, an alkyl group, or a cycloalkyl group,
• G is an oxygen atom, a sulfur atom, or NR202 where R202 is
• a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a heteroaryl group, and when G is an oxygen atom or a sulfur atom, R201 is a group other than a hydrogen atom, and
• g is an integer of 0 or 1;
• or
• a group represented by formula (Y) below:
• where R300 is an alkylene group or a silylene group having an alkyl group or an aryl group as a substituent,
• R301 is an alkyl group or an aryl group,
• R302, R303 and R304 are each an alkylene group,
• h, j, k and 1 are each an integer of 0 or 1, and
• i is an integer of 2 to 200;
• the plural i may be expressed in the same or different units,
• when a plurality of the R4 or R5 are present depending on the value of a or b, the plural R4 or R5 may be the same or different from each other;
• when two R4 or R5 are present adjacent to each other, these two adjacent R4 or R5 together may form, with carbon atoms to which the R4 or R5 are bonded, a ring that may contain an oxygen atom, a carbon atom, a sulfur atom, or a nitrogen atom,
• R6 is a phenylene group or a direct bonding and R7 is an aryl group or a heteroaryl group or a direct bonding, provided that one of the R6 and R7 is a direct bonding to an organic group,
• R8 and R9 are each the following group:
• a hydrogen atom;
• a hydroxyl group;
• an alkyl group;
• a cycloalkyl group;
• an alkoxy group;
• an alkoxyalkyl group;
• a formyl group;
• a hydroxycarbonyl group;
• an alkylcarbonyl group;
• an alkoxycarbonyl group;
• a halogen atom;
• an aralkyl group;
• an aralkoxy group;
• an aryl group;
• an aryloxy group;
• a heterocyclic group;
• or
• the group represented by Formula (Y), and
• the R8 and R9 together may form, with carbon atoms in the 13-position to which the R8 and R9 are bonded, an aliphatic ring having 3 to 20 carbon atoms, a fused polycyclic ring in which the aliphatic ring is fused with an aromatic ring or an aromatic heterocyclic ring, a 3- to 20-membered heterocyclic ring, or a fused polycyclic ring in which the heterocyclic ring is fused with an aromatic ring or an aromatic heterocyclic ring, and
• wherein a non-SO aromatic ring is an aromatic hydrocarbon ring or an aromatic heterocyclic ring containing neither a sulfur atom(S) nor an oxygen atom (O) therein, and
• wherein R3 has a molecular weight of less than 200.