Visible light absorption of green light-activated crosslinking reactants was quantitatively determined using an aqueous-based absorbance assay. Reactants were placed in DI water at the following concentrations: 1 mM Eosin Y (EY, photosensitizer), 125 mM triethanolamine (TEOA, initiator), 20 mM 1-vinyl-2-pyrrolidinone (VP, catalyst). Using a microplate reader, absorbance at 530 nm was recorded for solutions containing EY (dashed and dotted line), EY supplemented with TEOA (dashed line), EY supplemented with VP (dotted line), and EY supplemented with TEOA and VP (solid line).