100 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS . • • ,. • ... . Figure 3a. Blond hair, postbleached after 30 cycles of chlori•tion. Figure 3b. Blond hair, postdyed after 30 cycles of chlorination.

THE CHLORINE-HAIR INTERACTION 101 Figure 3c. Brown hair, postpermed after 30 cycles of chlorination. treatments alone caused little apparent damage to the fiber surfaces, and the fibers were very similar in appearance to the untreated control samples (Figure la-d). When cos- metic treatments preceded chlorination, the alteration of fiber surfaces and deformation from rubbing were similar to those seen in the chlorination of control fibers (Figure 2a-d). The wrinkled appearance is one that has generally been associated with the chlorination of keratin fibers and has been attributed to the disruption and loss of protein material through the epicuticle, resulting in collapsed scales (3,4). •q•en the app•ic-ation of the eosinerie treatment followed chlorination, the surfaces of the fibers were even more drastically affected (Figure 3a-c). Little or no scale structure was apparent, and fiber surfaces were quite smooth. Cuticular material appeared to have been removed with postchlorination bleaching and dyeing. The more drastically altered fiber surfaces resulted, however, in lower values of coefficient of friction. One possible explanation for the lower friction values observed is the sloughing off of the softened cuticle from the underlying structure, leaving a new rubbing surface which is harder. This is expected to be the case, as the new rubbing surface is less penetrated by the chemical treatment and is closer to the cortex, which is more crystalline. The values of percent weight loss are given in Table III. There was no significant difference between the values of weight loss of the prechlorination cosmetically treated samples and the control samples. Additionally, there was no significant difference be- tween the weight loss of the postchlorination permed samples and the control samples. However, the postchlorination bleached samples exhibited significantly greater weight loss than the other treatments by 10 hours of chlorination. The postdyed samples were