Provided is a thioether-functional, oligomeric polythiol having pendant hydroxyl functional groups, prepared by reacting together: (a) a compound having at least two thiol functional groups; and (b) a hydroxyl functional compound having triple bond functionality. Also provided are optical articles prepared from the reaction product of: (A) a reactive compound having functional groups that are reactive with active hydrogens; (B) a thioether-functional, oligomeric polythiol; and, optionally, (C) a compound different from (B) containing active hydrogens.