Preliminary exhaustion studies of spiroxazine dyes on polyamide fibers and their photochromic properties

The photosensitive spiroxazine dyes have been prepared to examine the practical dyeing feasibilities and behaviors. An interest on direct spiroxazine exhaustion to the polyamide substrates and its photochromism effects within the fiber molecules were investigated. The exhaustion (%) of the spiroxazine dyeings increased with increasing application temperatures. Successful spiroxazine exhaustion within the fiber molecules was determined from the photographs of the photochromism of the dyed substrates. When UV irradiation was subjected to the spiroxazine dyeings, the absorption spectra generated by photochromic reaction were clearly observed and its reversible decoloration behaviors responded rapidly in the dark.