Applicability of 2,3-dihydro-2-spiro-4’-[8′-aminonaphtalen-1′(4′H)-on]perimidine to dosimeters

The response of the photochromic compound 2,3-dihydro-2-spiro-4’-[8′-aminonaphtalen-1′(4′H)-on]perimidine (PNO-p) dispersed in a polystyrene (PS) and a polymethyl methacrylate (PMMA) film to X-ray irradiation was evaluated with the aim to develop an organic dosimeter. The effect of co-doping with the organic phosphor 2-(4-tert-butylphenyl)-5-(4-biphenylyl)-1,3,4-oxadiazole (b-PBD) on the sensitivity to X-ray irradiation was also determined. The photochromic reaction of PNO-p was induced by X-ray irradiation. The sensitivity of PNO-p in the PMMA films to X-ray irradiation was enhanced by co-doping with b-PBD. The stability of the isomer of PNO-p generated by photochromic reaction (open form of PNO-p) at room temperature under 575 nm irradiation was also investigated. Only 0.4% of the open form of PNO-p in the PS film was changed to the closed form at room temperature for 1 h. In addition, the open form of PNO-p was more stable against 575 nm irradiation in the PS films than in the PMMA film.