SU8 has been modified with photoinitiators Rose Bengal, H-NU 470 and H-NU 535, to conduct visible light lithography. The thermophysical properties of the lithographically transformed modified SU8 photoresins were investigated. The influence of the concentration of visible light photosensitizer and photoinitiator as well as exposure time to visible laser on thermal stability and curing kinetics were analyzed. Significant differences in the thermophysical properties were observed in these three photoinitiator groups of modified SU8 photoresins. These results provide with usable quantitative information regarding resin formulation to optimize lithography processing parameters, and therefore, the ultimate properties of lithographically formed microstructures. (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 47-54, 2010