ESR g-shift measures pyrolytic deoxygenation and the effect of flame retardants

The theory of g‐factors in aromatic radicals proposed by McConnell and Robertson and the statistical theory of Boltzmann were used to show that a small decrease in the g‐factor of the ESR spectrum of the pyrolysis residue of cellulosic materials is proportional to a small decrease in the ratio of the bound oxygen atoms to that of the carbon atoms in the system. An average g‐factor decrement was defined and used to evaluate the effect of a flame retardant on the rate of deoxygenation in the thermal decomposition of cellulosic materials at various temperatures.