Comparative-Study of Stone-Ground Wood Pulp and Native Wood .2.Comparison of the Fluoresence of Stone-Ground Wood Pulp and Native Wood

The fluorescence spectra of paper made from high yield pulp (stone-ground wood pulp (SGWP)) and of thin sections of a softwood (Abies) were recorded and shown to be very similar. The fluorescence from a wood sample, previously reduced with sodium borohydride, shows a biexponential decay, with the magnitude and contribution of the components being dependent on wavelength. From the bleaching kinetics of the chromophores producing the fluorescence, it is concluded that the emission observed for paper made from high yield pulp and for wood originates mainly from lignin and not as previously suggested from cellulose. The steady state and dynamic fluorescence of some lignin model molecules adsorbed on cellulose indicates that the fluorescence of wood, which has been reduced by sodium borohydride, might -originate to some extent from coniferyl alcohol and biphenyl-type structures.