Fig. 1. Most pronounced changes in chemical bonds during the photo-initiated polymerization process.

a shows the absorbance spectra for LT sample, where it is clearly observed that the C=C monosubstituted stretching peak at (1636 ± 1) cm⁻¹ vanishes completely during UV-induced polymerization, allowing nearly 100% conversion. b shows the absorbance spectra for the HT samples, where the C=C monosubstituted stretching peak at (1636 ± 1) cm⁻¹ is found to only decrease in size but does not vanish completely. The graphs show the pristine sample, and polymerized samples after 0.1 s, 0.2 s, 0.3 s, 0.8 s, 1.0, 1.5 s, 2.0 s, 3.0 s, 4.0 s, 10.0 s, and 60.0 s of UV exposure. c Conversion of the two polymer resins measured using FTIR, LT in black and HT in red. The resins are polymerized step-wise and full FTIR spectra are recorded for each step, from these spectra the relative intensity of the C=C monosubstituted stretching peak at (1636 ± 1) cm⁻¹ is used to calculate the conversion. The data is then fitted using an exponential function represented by the solid lines. The fitting parameters are presented in Supplementary Table 3.