Unusual phosphorescence and its pressure dependence in 4-N,N-dimethylaminobenzonitrile dissolved in solid polymers

Light-induced phosphorescence of 4-N,N-dimethylaminobenzonitrile (DMABN) dissolved in solid polymer has been observed for the first time. This unusual phosphorescence develops after continuous illumination of the sample at room temperature. The phosphorescence follows an initiation period the duration of which depends strongly on the exciting light intensity, concentration of solute in the polymer, pressure and the previous treatment of the sample. Under continuous illumination, the overall shape of the phosphorescence intensity curve versus time depends also on the exciting light intensity and concentration. At pressures higher than 13 kbar light-induced phosphorescence is no longer observed.