Enhanced UV transparency in phosphate glasses via multi-wall carbon nanotubes
Multi-wall carbon nanotubes are systematically explored for the first time as a means to obtain an enhanced ultraviolet (UV) transparency in melt-quenched phosphate glasses. An optical characterization is carried out by UV/Vis transmission and photoluminescence spectroscopy including time-resolved measurements. 31P nuclear magnetic resonance, Raman microspectroscopy, differential scanning calorimetry and X-ray photoelectron spectroscopy are employed to further investigate the source of the improved UV light transmission. The data suggest that the formation of P–O–C bonds is connected to the enhanced UV transparency. A model is presented accounting for the incorporation of carbon into the phosphate network facilitated by the creation of intermediate reactive oxygen species.