Abstract: A chromene compound having a short fading half period, especially, a short fading half period even at a low temperature in a general-purpose polymer solid matrix. The chromene compound is represented by the following formula (1). wherein R1 is a hydroxyl group or the like, R2 and R3 are each an aryl group or the like, C* is a spiro carbon atom, a spiro ring A represented by the following formula is a saturated hydrocarbon ring having 4 to 12 ring member carbon atoms or the like, and at least one ring member carbon atom constituting the ring A is a group represented by the following formula (4), and X is a divalent group such as arylene group, wherein R7 and R8 are each a cycloalkyl group or the like.

Abstract: A process of producing a urethane (meth)acrylate monomer having a low acid value and a low content of a hardly soluble high-molecular weight impurity which is crosslinked high-dimensionally, comprising the steps of: (1) contacting a first solution containing a urethane (meth)acrylate monomer having an acid value of more than 0.2 mgKOH/g and an organic solvent to a water-containing adsorbent capable of adsorbing an acid component to obtain a second solution containing a urethane (meth)acrylate monomer having an acid value of not more than 0.2 mgKOH/g, the organic solvent and more than 5,000 ppm (mass) of water based on the urethane (meth)acrylate monomer; (2) contacting the second solution to a dehydrating agent to obtain a third solution containing not more than 5,000 ppm (mass) of water based on the urethane (meth)acrylate monomer; and (3) removing the organic solvent from the third solution.

Abstract: A novel photochromic compound which develops a color of a neutral tint and has high color optical density, high fading speed and excellent durability. The present invention is a chromene compound having an indeno(2,1-f)naphtho(1,2-b)pyran structure as the basic skeleton in which a hetero ring having two hetero atoms including at least one sulfur atom is directly bonded to the 6-position and the 7-position of the indeno(2,1-f)naphtho(1,2-b)pyran structure via the hetero atom like the compound represented by the following formula (18).

Abstract: A chromene compound having a short fading half period, especially, a short fading half period even at a low temperature in a general-purpose polymer solid matrix. The chromene compound is represented by the following formula (1). wherein R1 is a hydroxyl group or the like, R2 and R3 are each an aryl group or the like, C* is a spiro carbon atom, a spiro ring A represented by the following formula is a saturated hydrocarbon ring having 4 to 12 ring member carbon atoms or the like, and at least one ring member carbon atom constituting the ring A is a group represented by the following formula (4), and X is a divalent group such as arylene group, wherein R7 and R8 are each a cycloalkyl group or the like.

Abstract: The chromene compound is represented by the following formula (I), wherein R3 at the 11-position is a sulfur-containing substituent selected from the group consisting of thiol group, alkylthio group, alkoxyalkylthio group, haloalkylthio group, cycloalkylthio group, arylthio group, heteroarylthio group, sulfonyl group and sulfinyl group, R1 and R2 at the 6-position and the 7-position are a combination of an aryl group or a heteroaryl group and an electron donating group having a Hammett constant ?p of ?0.1 or less, or R1 and/or R2 is sulfur-containing substituent selected from thiol group, alkylthio group, alkoxyalkylthio group, haloalkylthio group, cycloalkylthio group, arylthio group and heteroarylthio group.

Abstract: A photochromic chromene compound having an indeno(2,1-f)naphtho(1,2-b)pyran structure as its basic skeleton, an aryl group or a heteroaryl group at the 6-position carbon atom of the structure and an electron donor group having a Hammett constant ?p of not more than ?0.1 at the 7-position carbon atom.

Abstract: A novel photochromic compound which develops a color of a neutral tint and has high color optical density, high fading speed and excellent durability. The present invention is a chromene compound having an indeno(2,1-f)naphtho(1,2-b)pyran structure as the basic skeleton in which a hetero ring having two hetero atoms including at least one sulfur atom is directly bonded to the 6-position and the 7-position of the indeno(2,1-f)naphtho(1,2-b)pyran structure via the hetero atom like the compound represented by the following formula (18).

Abstract: A chromene compound which develops a color of a neutral tint and has little initial coloration, high double peak characteristic and high color development sensitivity, rarely experiences the reduction of color optical density though it has high fading speed, is excellent in the durability of photochromic properties and can dissolve in a monomer composition which will become a substrate for optical articles in a high concentration, and a photochromic curable composition comprising the chromene compound and polymerizable monomers. The chromene compound is represented by the following formula (1).

Abstract: A process of producing a urethane (meth)acrylate monomer having a low acid value and a low content of a hardly soluble high-molecular weight impurity which is crosslinked high-dimensionally, comprising the steps of: (1) contacting a first solution containing a urethane (meth)acrylate monomer having an acid value of more than 0.2 mgKOH/g and an organic solvent to a water-containing adsorbent capable of adsorbing an acid component to obtain a second solution containing a urethane (meth)acrylate monomer having an acid value of not more than 0.2 mgKOH/g, the organic solvent and more than 5,000 ppm (mass) of water based on the urethane (meth)acrylate monomer; (2) contacting the second solution to a dehydrating agent to obtain a third solution containing not more than 5,000 ppm (mass) of water based on the urethane (meth)acrylate monomer; and (3) removing the organic solvent from the third solution.

Abstract: A photochromic chromene compound having an indeno(2,1-f)naphtho(1,2-b)pyran structure as its basic skeleton, an aryl group or a heteroaryl group at the 6-position carbon atom of the structure and an electron donor group having a Hammett constant ?p of not more than ?0.1 at the 7-position carbon atom.