Concentration-dependent fluorescence behaviour of oxazine 750 and rhodamine 6G in porous silicate xerogel monoliths Original Research Article

The concentration dependent fluorescence quantum efficiency ΦF and fluorescence polarization PF of rhodamine 6G (10−5 to 0.8 mol/dm3) and oxazine 750 (10−5 to 0.01 mol/dm3) in porous silicate xerogel monoliths have been studied. The xerogel pores were filled with formamide. The decrease of ΦF is due to Förster-type energy transfer to closely spaced pair quenching centers, and the decrease of PF is caused by reorientation of emission transition dipole moments due to energy transfer from excited to unexcited molecules.