Optical and photophysical investigation of Meso, Proto and Hematoporphyrin(IX)dimethylester doped hybrid borate glasses

Hybrid borate glasses containing different concentrations (0.5–2.0 mg in 12 g of boric acid) of Mesoporphyrin(IX)dimethylester, Protoporphyrin(IX)dimethylester and Hematoporphyrin(IX)dimethylester were prepared by rapid melt quench technique at 230 °C. The hybrid glass samples were characterized by X-ray diffraction, optical absorption, steady state and time-resolved fluorescence emission. The optical absorption spectrum shows red-shift in Soret band along with change in Q-band pattern. The intensity of Q-band was found to increase with increase in the concentration of porphyrin in the glass. Steady state emission spectrum shows strong S2→S0 emission in the range 462–495 nm and blue shift in S1→S0 emission. Time-resolved fluorescence emission and fluorescence excitation spectra showed that different structures of porphyrins were exist in the glass samples. The variation in the spectral behaviour in the glass was correlated with those in solution medium and possible structures of porphyrin in borate glass were explored.

Research Highlights
► Novel porphyrin doped hybrid borate glasses were prepared by rapid melt quench technique.
► The optical absorption spectrum reveals that structure of the porphyrin inside the borate glass was inherently modified.
► Steady state emission spectrum shows unusual strong S2→S0 emission in the range 462–495 nm and blue shift in S1→S0 emission in the range 550–617 nm.
► Time-resolved fluorescence emission decay shows three distinct fluorescent species exists in the glass.