COMPARATIVE-STUDY OF STONE-GROUND WOOD PULP AND NATIVE WOOD .2. COMPARISON OF THE FLUORESCENCE OF STONE-GROUND WOOD PULP AND NATIVE WOOD

The fluorescence spectra of paper made from high yield pulp (stone-gro und wood pulp (SGWP)) and of thin sections of a softwood (Abies) were recorded and shown to be very similar. The fluorescence from a wood sa mple, previously reduced with sodium borohydride, shows a biexponentia l decay, with the magnitude and contribution of the components being d ependent on wavelength. From the bleaching kinetics of the chromophore s producing the fluorescence, it is concluded that the emission observ ed 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 adsorbe d on cellulose indicates that the fluorescence of wood, which has been reduced by sodium borohydride, might -originate to some extent from c oniferyl alcohol and biphenyl-type structures.