The behaviour of nitro-aromatic amines 4-nitro-1-naphthylamine (NNA), N-acethyl-4-nitro-1-naphthylamine and N,N-dimethyl-4-nitroaniline, in the presence of a tertiary amine such as N,N-dimethylaniline as photoinitiators of the dodecyl acrylate polymerisation has been studied by Real-Time IR spectroscopy upon UV exposure and the results compared with those obtained with 4-nitroaniline (pNA). The rate and quantum yield of polymerisation as well as the residual unsaturation in the cured polymer result are strongly dependent on the photoinitiator nature. The formulation based on the NNA compound improves the polymerisation activity of pNA exhibiting a reaction rate up to 2.1 M s(-1) and reaching a conversion of nearly 85%.