This paper was focused on the synthesis and properties of a water-soluble resin having tertiary amine oxide side substituents. First, 3-(dimethylamino)propanoic acid was synthesized through the addition reaction of dimethylamine with methyl acrylate, followed by hydrolysis of the adduct. Then, 3-(dimethylamino) propanoic acid was oxidized with hydrogen peroxide to obtain 3-(dimethylamino) propanoic acid oxide. Finally, epoxy phenolic was reacted with 3-(dimethylamino) propanoic acid oxide to get the end product. Thermal behaviors and thermo-induced solubility change of the prepared resin were investigated. It was found that the tertiary amine oxide resin was still water soluble even after heating at 120 degrees C for 1 h. However, it readily became completely water insoluble after heating at 170 degrees C for a short period of time. Thin films were prepared with the aqueous solution of the tertiary amine oxide resin and an infrared (IR) dye with maximum absorption at 830 nm. The films could absorb 830 nm IR imaging radiation and give negative image after developing with neutral water. The water-soluble thermo-sensitive resin might be used in chemical-free thermal laser imaging applications.