The search for photosensitive alkoxyamines represents a huge challenge. The key parameters governing the cleavage process remain unknown. The dissociation process of light sensitive alkoxyamines is studied as a function of their chemical structures. The photochemical properties of 6 selected compounds are investigated by ESR and laser flash photolysis. It is found that (i) the selectivity of the cleavable N–O vs. C–O bond and (ii) the efficiency of the nitroxide formation are strongly related to the alkoxyamine structure. The distance between the chromophore and the aminoxy group is a key parameter for an efficient pathway of the radical generation as displayed by the photopolymerization ability of these alkoxyamines.