Poly(trimethylene carbonate) (PTMC) is a well-known biodegradable polymer with good biocompatible properties which make it suitable for biomedical applications. Poly(5-[2-{2-(2-methoxyethoxy)ethyoxy}-ethoxymethyl]-5-methyl-1,3-dioxa-2-one) (PTMC-MOE3OM) and copolymers, bearing oligo ethylene glycol (OEG) at the side chain of PTMC backbone, were selected to investigate the cloud point behavior by solvents such as PBS, water, 10% ethanol solution and various ionic strengths. A pH-responsive copolymer, poly(TMCM-MOE3OM-co-(5-methyl-5-carboxylic-1,3-dioxane-2-one)) as carboxylic acid carbonate showed a decreased critical temperature at pH 2. Photo-responsive copolymer, poly(TMCM-MOE3OM-co-coumarin derivatives) bearing 1% and 10% of photo-induced molecules (7-[(5-(5-methyl-1,3-dioxa-2-one)methoxy)]-methoxy coumarin (TMCM-coumarin)) exhibited a low cloud point because of the hydrophobic moieties. Meanwhile, alternative coumarin polymer including 2% of 4-methyl-7-[(5-(5-methyl-1,3-dioxa-2-one)methoxy)butoxy)]-methoxy coumarin (TMCM-4-methyl-coumarin) has been successfully synthesized and copolymerized as a novel molecule. The various combinations of monomers were studied and the significant properties were determined via external triggers after copolymerization. This study showed basically synthetic progress toward designs and trivial rationalization of thermoresponsive copolymers close to body temperature. At present, various pendant groups as side part affect to the lower critical solution temperature (LCST) and biodegradable polymer in order to utilize the actual external stimuli application. (c) 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 3466-3474