The behavior of excited centers due to oxygen impurities in the AlN la
ttice is reported for the first time by thermoluminescence (TL), studi
es between 77 and 550 K after 253.7 nm UV excitation. According to the
origin of the product, the TL brings to the fore important difference
s due essentially to the synthesis process. The measurements of fluore
scence let appear emission bands around 3.2 eV identified as due to su
bstitutional oxygen and a very narrow one at 2.1 eV characteristic of
Mn4+ ions observed before by EPR measurements. At last, measurements o
f FTIR confirm, as supposed from TL, the presence of gamma-AlON in one
of the studied samples even if it is under the form of marks only.