  A spontaneous luminescence is reported when epoxy resin samples are heated in
air. This phenomenon is very sensitive to the nature of the atmosphere. The
same treatment in nitrogen leads to an extinction of the luminescence. The
emission process is restored when samples are kept for a sufficient time in
air. In order to better understand this phenomenon, we have investigated the
luminescence of the elementary constituents of the epoxy (resin and hardener)
when heated in air and nitrogen, as well as during resin curing in the same
atmospheres. It appears that the emission process is linked with the presence
of oxygen. Although the kinetics of the luminescence can differ depending on
the nature of the sample (cured resin, resin during curing, liquid components),
the emission spectra are the same during resin curing and upon heating of the
cured resin and hardener. The emission spectrum of the base resin is different.
It is concluded that the light results from a chemiluminescence process during
oxidation.
