Photo-crosslinkable, fumaric acid monoethyl ester-functionalized poly(trimethylene carbonate) oligomers were synthesized and copolymerized with N-vinyl pyrrolidone (NVP) and vinyl acetate (VAc) to form biodegradable polymer networks. The copolymerization reactions were much faster than homopolymerization of the fumarate end-groups of the macromers. The hydrophilicity of the networks could by varied by mixing NVP and VAc at different ratios. The prepared network extracts were compatible with NIH 3T3 fibroblasts. Release of vitamin B12, used as a model drug, could be tuned by varying network hydrophilicity and macromer molecular weight. A more hydrophilic and less densely crosslinked network resulted in faster release.