This paper reports a non-destructive method for evaluating hair interior and surface damage based on near-infrared (NIR) diffuse reflectance (DR) spectroscopy. It is important to know the extent of chemical damage in the interior and surface proteins of the hair in order to choose an appropriate restoration agent or chemical treatment. Unfortunately, though there are many simple and non-destructive methods for evaluating the hair surface, the existing evaluation methods for monitoring chemical changes in the interior proteins are very complicated and destructive. Therefore, we have attempted to develop a new non-destructive method to evaluate the damage of the hair interior and surface simultaneously by using NIR-DR spectroscopy. The key to this study was the combined application of NIR-DR spectroscopy and principal component analysis to development of a method for the evaluation of hair damage and finding the most suitable wavenumber region (5060—4500 cm-1) for this evaluation. In this study, we developed a new evaluation method that can indicate hair interior and surface damage conditions induced by chemical treatments in a simple, rapid, non-destructive manner based on NIR-DR using a fibre probe on hair
Paper presented at the IFSCC International Conference 2005, Florence, Italy.