The extensive use of N-p-tolylglycine (NTG) and analogous compounds in adhesive bonding technologies requires a better understanding of their role in initiating free-radical polymerization. The fast oxidation and reduction reactions of NTG proceed via the formation of various free radicals and radical cation and anion intermediates. These intermediates were identified and their reactivity with oxygen, to produce the corresponding peroxyl radicals, was measured. Hydroxyl radicals (OH) were used to initiate oxidation reactions of NTG, while the reduction reactions were initiated with hydrated electrons (e(aq)(-)). OH radicals react with NTG predominately by addition to the aromatic ring followed by OH-elimination to produce NTG(+). radical cations. In the presence of oxygen, the OH-NTG(.) adduct also reacts with oxygen to produce peroxyl radicals. The reaction of NTG with e(aq)(-) forms the radical anion, which subsequently protonates on the aromatic ring to produce cyclohexadienyl radicals, or undergoes an amine elimination to yield an acetic acid free radical and 4-methylaniline. Hydroperoxyl radicals (HO2.) abstract hydrogen from the alpha position of NTG to form the corresponding alkyl free radical.