FT-Raman spectra were obtained from undyed poplin cotton fabric and from the same fabric
differently dyed with a bi-functional reactive dye, Cibacron C (molecular structure unknown); the four series
of the dyed samples each contained the dye in a different form-unfixed, ammonia-treated/unfixed, fixed, and
ammoniatreated/fixed. The spectra were dominated by the dye, but the different states of the dye were not
obviously differentiated. Application of principal component analysis showed that the spectral groups of the
four different dye states can be discriminated from each other and from that of the undyed cotton. Further,
for each series of the dyed fabrics, which contain samples with different amounts of dye, the individual dye
concentration subgroups are distinguished.
