| abstract |
The present invention provides an optical composition that can produce an optical article in which defects in the external appearance, such as opacity and optical distortion, during lens base material production are reduced, and in addition, in the case where a photochromic compound is added, that can form a photochromic cured body having excellent photochromism and mechanical strength. This invention also provides a polyrotaxane that is used for the composition. The polyrotaxane is a polyrotaxane having a combined molecule structure composed of an axle molecule and a plurality of cyclic molecules clathrating the axle molecule and satisfies at least one of (X) and (Y). (X) A side chain having secondary or tertiary hydroxyl groups is introduced to at least a part of the cyclic molecules of the polyrotaxane. (Y) The polyrotaxane is a polyrotaxane in which a side chain having a group represented by -A (where A is an organic group having at least one hydroxyl group) is introduced to at least a part of the cyclic molecules of the polyrotaxane, and the pKa of the hydroxyl groups of the compound represented by H-A is at least 6 and less than 14. |