The trithiocarbonate end groups of polymers prepared by RAFT polymerization are converted into colorless and stable thioethers in a one-pot process that combines aminolysis of the trithiocarbonate functions and Michael addition of the resulting thiols to alpha, beta-unsaturated carbonyl derivatives. This post polymerization procedure, which is carried out under mild conditions to near quantitative conversion, is described in he case of a telechelic poly(N-isopropylacrylamide) sample bearing isobutylsulfanylthiocarbonylsulfanyl end groups. The chemical composition, purity, and molar masses of the modified polymers are assessed by GPC, H-1 NMR spectroscopy and UV-vis spectroscopy, which together demonstrate the efficiency of the method and confirm that the molecular weight and polydispersity of the precursor RAFT polymer are not affected by the treatment.