H. Tylli et al., THE EFFECT OF PHOTOIRRADIATION ON HIGH-YIELD PULPS - SPECTROSCOPY ANDKINETICS, Journal of photochemistry and photobiology. A, Chemistry, 87(2), 1995, pp. 181-191
Fluorescence, UV-visible reflectance and diffuse reflectance IR Fourie
r transform spectroscopy were used to study the changes caused by phot
oirradiation of unbleached, peroxide-bleached and ozone-bleached mecha
nical and chemimechanical pulps. Irradiations were performed selective
ly at 350 nm and emission spectra were obtained using the same excitat
ion wavelength. Kinetic curves were obtained by plotting the integrate
d emission intensity against the irradiation time. Different domains o
f photochemical behaviour were observed for unbleached and ozone-bleac
hed mechanical pulps. For peroxide-bleached samples, an exponential de
cay of the emission intensity was observed on irradiation, accompanied
by a shift in the emission maximum to longer wavelengths. The observe
d emission spectra were deconvoluted into several components, and atte
mpts were made to identify the chromophores causing the emission by co
mparison with the fluorescence spectra of model compounds.