Photochromic article

A photochromic article comprising:

• (A) a substrate;
• and
• (B) a photochromic layer residing over at least a portion of said substrate, wherein said photochromic layer is formed from a curable photochromic composition comprising,
• (a) a polyol component, wherein said polyol component comprises a polycarbonate diol having a hydroxyl equivalent weight of at least 1300;
• (b) an isocyanate component comprising at least one of an unblocked polyfunctional isocyanate comprising at least two unblocked isocyanate groups, a blocked polyfunctional isocyanate comprising at least two blocked isocyanate groups, or combinations of said unblocked polyfunctional isocyanate and said blocked polyfunctional isocyanate;
• and
• (c) at least one photochromic compound,
• wherein said curable photochromic composition has an equivalents ratio of (i) unblocked isocyanate equivalents and blocked isocyanate equivalents to (ii) hydroxyl equivalents of said polyol component of at least 5:1, and
• wherein said photochromic article exhibits a T1/2 (Fade Half Life) at 23° C. of less than or equal to 60 seconds,
• wherein at least one photochromic compound is selected from indeno-fused naphthopyrans comprising an indeno [2′,3′:
• 3,4] naphtho [1,2-b] pyran core structure represented by the following Formula (III),
• wherein said indeno [2′,3′:
• 3,4] naphtho [1,2-b] pyran core structure comprises,
• bonded to Position-3, B and B′, wherein B and B′ are each independently selected from the group consisting of unsubstitued phenyl, and substituted phenyl, wherein the phenyl substituents are each independently selected from the group consisting of fluoro, morpholino, pyrimidino, piperidino, and -ORd, wherein Rd is selected from linear and branched C1-C10 alkyl,
• bonded to Position-6, hydrogen, or -ORa, wherein Ra is linear or branched C1-C10 alkyl,
• bonded to Position-7, an electron-donating group selected from the group consisting of alkoxy, morpholino, and piperidino,
• bonded to Position-11, a group selected from the group consisting of phenyl, fluoro substituted phenyl, perfluroalkyl substituted phenyl, morpholinocarbonyl, and piperidinocarbonyl;
• bonded to Position-13, Rb and Rc, wherein Rb and Rc are each independently selected from linear or branched C3-C10 alkyl;
• and
• hydrogen is bonded to each of Positions 1, 2, 5, 8, 9, 10, and 12.