Effect of method of preparation and drying time on photophysical properties of coumarin 1 laser dye embedded in HCl catalysed sol–gel glasses

Coumarin 1 (C1) dye is impregnated in transparent sol–gel glass samples prepared by sol–gel process using three methods – (I) using HCl as catalyst and glycerol as a drying control chemical additive (DCCA), (II) using HCl as catalyst at 60 °C subsequent drying at room temperature, and (III) using HCl as catalyst at 60 °C and heated at 600 °C for 3 h. The sol–gel matrices prepared by Methods I and II are given dip treatment with methanol/distilled water (50/50 volume) for 16 h before dipping into dye solution. The effect of method and drying time of matrix on spectroscopic properties of C1 dye doped glass samples has been studied. The optical density (OD) at absorption maximum wavelength and fluorescence intensity (FI) at fluorescence maximum wavelength of all C1 dye doped samples prepared by Methods I and II decrease, where as there is no change in photophysical properties (OD/FI) is observed in samples prepared by Method III with the time of drying of the sol–gel samples. These absorption/fluorescence properties of C1 dye in sol–gel glass matrices are compared with its respective properties in methanolic solution in acidic environment.