Polymers stabilized by esters of phosphinodithioic acids

A polymeric composition stabilized against degradation by ultraviolet light by an effective amount of a compound of the formula:

• ##STR9## wherein R.sub.1 and R.sub.2 are selected from alkyl;
• cycloalkyl;
• alkyl substituted by hydroxy, alkoxy, cyano, chloro, bromo, or fluoro;
• aryl;
• aralkyl;
• aryl and aralkyl substituted by one or two lower alkyl, lower alkoxy, hydroxy, or halogen on the aryl moiety thereof;
• n is 1 or 2;
• and, when n is 1, R.sub.3 is selected from alkyl;
• cycloalkyl;
• alkyl substituted by hydroxy, alkoxy, cyano, chloro, bromo, or fluoro;
• alkylthioalkyl;
• aralkyl;
• aryl;
• aralkylthioalkyl;
• and aralkyl, aryl, or aralkylthioalkyl substituted by one or two lower alkyl, lower alkoxy, hydroxy, or halogen on the aryl moiety thereof, and, when n is 2, R.sub.3 is selected from alkylene;
• hydroxyalkylene;
• oxybis and thiobis(alkylene);
• arylene;
• or arylene substituted by lower alkyl, lower alkoxy, hydroxy, or halogen.