The photochemical properties of two new photocleavable alkoxyamines bearing a benzophenone-derived chromophore were studied by electron spin resonance (ESR). The C-O bond cleavage has been demonstrated and the photolysis rate constants (k(d)) determined over a large range of light intensity through the monitoring of the nitroxide concentration in aerated conditions. The obtained kinetic data highlight for the first time the linear dependence of kd on the light intensity for alkoxyamines: this should be a driving factor for nitroxide mediated radical photo-polymerization (NMP2).