for
non-bridging oxygen (NBO) luminescence center in silica glass
[21] and irradiated α-quartz crystal [22]. We had obtained NBO in
non-irradiated α-quartz crystal just by heat treatment. No ESR
signal was detected in heat treated sample after irradiation with
ArF laser at room temperatures. Heat treatment to 550 °C diminishes
UV luminescence in P-doped α-quartz crystal, however not
completely Fig. 2. Therefore it is possible conclude that UV related
centers and center of yellow luminescence corresponds to different
position of phosphorus in quartz. Yellow luminescence with
described above properties disappear after treatment at 550 °C. It could be assumed that phosphorus substituting silicon in tetrahedron
corresponds to more stable UV center. However heat
treatment to 660 °C practically destroys UV luminescence center.
In sample heat to 660 °C NBO center was not observed after irradiation
with ArF laser. Phosphorus relatively easier transforming to
sediment could correspond to some structures containing P2O5
and water and OH groups. We had achieved some restore of heat
treated sample properties, however not completely. Restoration
procedure consists in keeping of treated sample at 400 °C during
many hours.