Both type of luminescence UV and yellow were ascribed to different defects containing phosphorus.
P-doped α-quartz sample heated at 550 °C become opalescent. IR spectra related to water and OH
groups are changed. Photoluminescence intensity of all three bands, UV (250 nm), yellow (600 nm) and
red (740 nm) strongly diminished and disappeared after heating to 660 °C. Radiation induced red
luminescence of non-bridging oxygen luminescence center (NBO) appeared in crystal after heat treatment.
We had observed a crystalline version of this center (Skuja et al., Nuclear Instruments and Methods
in Physics Research Section B Beam Interactions with Materials and Atoms. 2012; 286: pp. 159–168).
Effect of heat treatment explained as sedimentation of phosphorus in some state. Keeping of treated
sample at 450–500 °C leads to partial revival of ability to create yellow luminescence center under
irradiation.