Luminescence spectra of pyrolytic boron nitride are obtained upon photoexci
tation at 315, 365, and 403 nm. It is shown that luminescent centers repres
ent intrinsic defects which have a quasi-continuous band of levels in the e
nergy gap and are localized in the regions near the boundary of grains. The
spectra of radiation-induced luminescence (RIL) of pyrolytic boron nitride
are obtained upon its irradiation by 8.13 MeV-protons with an intensity of
3.2 x 10(12) cm(-2) s(-1). A linear irreversible decrease in the RIL inten
sity with increasing irradiation dose was observed. At a dose of 1.88 x 10(
16) cm(-2), the RIL intensity saturates. The saturation effect is connected
with radiation-induced structural changes on the surfaces of the grains ca
used by the electron-hole relaxation and a considerable increase in the sel
f-diffusion coefficients.