To demonstrate the utility of NMR in monitoring polymerization kinetics of industry-relevant polymer resins, we designed an in situ NMR set-up wherein the resin is kept separated from the locking solvent (see Figure ). A fiber optic cable directed UV-light into a concentric capillary (O.D. = 4 mm), which was placed within the larger NMR tube (O.D. = 5mm). The annulus between the tubes contained the photopolymerizable resin, and this resin was photoexcited by the frosted fiber optic tip in a uniform, cylindrical fashion. In addition to housing the fiber optic, the concentric capillary also served the purpose of containing deuterated solvent (D2O) and internal standard (acetic acid).