Polymers of diallyl amino-4-(2,2,6,6-tetramethyl piperidyl) carboxylic acid esters and amides are provided, having a molecular weight within the range from about 800 to about 20,000, and derived from a monomer having the formula: ##STR1## wherein: R is alkylene or alkyleneoxy having from one to about six carbon atoms and m is 0 or 1;R.sub.1 is selected from the group consisting of hydrogen; oxyl; alkyl and hydroxyalkyl having from one to about eighteen carbon atoms; alkylaryl having from seven to about eighteen carbon atoms; epoxy alkyl having from three to about eighteen carbon atoms; and acyl having from two to about eighteen carbon atoms; andY is selected from the group consisting of ##STR2## where R.sub.2 and R.sub.3 are hydrogen or alkyl having from one to about eight carbon atoms and n is 0 or 1;Z is selected from the group consisting of ##STR3## in which R.sub.4, R.sub.5 and R.sub.6 are selected from the group consisting of hydrogen; alkyl having from one to about eighteen carbon atoms; cycloalkyl having from three to about twelve carbon atoms; and aryl having from six to about thirty carbon atoms; as well as stabilized synthetic resin compositions having an improved resistance to deterioration by light and containing such a polymer.