NEAR-INFRARED DYES ENCAPSULATED IN SOL-GEL MATRICES

Near-infrared dye oxazine-1 was introduced into gel glasses by the sol-gel method from TEOS and TMOS. The fluorescence properties of oxazine-1 were preserved in these matrices. The entrapment of 1,1',3,3,3',3'-hexamethylindotrycarbocyanine iodide (HITC) into gel glasses required dye protection from chemical degradation and was obtained from TMOS by producing high-density matrices upon prolonged aging of H2O/TMOS = 1 (molar ratio). Alternative strategies to protect HITC inside gel glasses were achieved by using a combination of sol-gel techniques with poly(methyl methacrylate) (PMMA) for the formation of mixed matrices of silica gel-PMMA glasses, or by copolymerization of TMOS with titanium tetraethoxide (TEOT) for the formation of gel glasses with a mixed TiO2-SiO2 composition, or by encapsulation of HITC with the aid of surface-active agents (SAA). The fluorescence and IR spectral behavior of the doped materials at different reaction conditions were studied.