370 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS sequence always alleviated that damage. In the case of the four hour bleach treatment, the improvement in yield stress after the application of conditioner resulted in values higher than those of the ungroomed sample. SUMMARY A variety of methods were combined to quantify the extent of primary damage from chemical changes introduced during oxidation of hair. Methods for detecting damage were chosen to evaluate surface or structural changes. Different levels of damage were achieved by changing the time of treatment in 6% H202 or the treatment process (hydrogen peroxide vs a commercial bleach creme). Surface changes increased with peroxide treatment times. The four hour peroxide treat- ment resulted in the greatest surface damage. Surprisingly, the commercial bleach creme caused much less surface (by SEM and wettability analyses) than structural damage. Although structural changes also increased with peroxide treatment time, some methods found the four hour peroxide treatment more damaging than the commercial bleach creme and others found the commercial product most damaging. Additional major structural damage was shown in successive perm treatments on unbleached and bleached hair. We explored the possibility that oxidative damage, as experienced during bleaching of hair, leaves the fibers susceptible to secondary damage during subsequent grooming. Grooming processes were simulated by combing, shampooing, and conditioner treat- ments before combing. We found that combing produced secondary damage and that conditioner use reduced or prevented the damaging effects of combing. Damage from combing was more severe in bleached than in unbleached hair. The application of conditioner after shampooing resulted in less damage in both bleached and unbleached hair. Attempts to correlate the various damage analyses and to draw conclusions about the relative effects of surface and bulk damage are currently underway on an expanded data base and will be the subject of a subsequent paper. ACKNOWLEDGMENTS The work reported here was conducted as part of a project, Analysis and Quantification of Hair Damage, sponsored by a group of corporate TRI/Princeton participants. We acknowledge the contributions of our colleagues, Irene Bradford, Rudy Turner (de- ceased), and Chi Wang. REFERENCES (1) R. Beyak, C. F. Meyer, and G. S. Kass, Elasticity and tensile properties of human hair. I. Single fiber test method, J. Soc. Cosmet. Chem., 20, 615-626 (1969). (2) C. R. Robbins and C. Kelly, Amino acid analysis of cosmetically altered hair, J. $oc. Cosmet. Chem., 20, 555-564 (1969). (3) C. R. Robbins and C. H. Kelly, Amino acid composition of human hair, Text. Res. J., 40, 891-895 (1970).

EVALUATION OF HAIR DAMAGE 37 ! (4) (5) (6) (7) (8) (9) (10) (12) (13) (14) (15) (16) L. J. Wolfram and M. K. D. Lindemann, Some observations on the hair cuticle,J. Soc. Cosmet. Chem., 22, 839-850 (1971). V. N. E. Robinson, A study of damaged hair, J. Sac. Cosmet. Chem., 27, 155-161 (1976). M. L. Garcia, J. A. Epps, R. S. Yare, and L. D. Hunter, Normal cuticle wear pattern in human hair. J. Soc. Cosmet. Chem., 29, 155-178 (1978). C. Zviak, in The Science afHair Care, C. Zviak, Ed. (Marcel Dekker, New York, 1986), pp. 195-200. Y. K. Kamath, C. J. Dansizer, and H.-D. Weigmann, Wettability of keratin fiber surfaces, J. Sac. Cosmet. Chem., 28, 273-284 (1977). B. A. Bidlingmeyer, S. A. Cohen, and T. L. Tarvin, Rapid analysis ofamino acids using pre-column derivization, J. Chram., 336, 93-104 (1984). Y. K. Kamath, S. B. Hornby, and H.-D. Weigmann, Mechanical and fractographic behavior of Negroid hair, J. Sac. Cosmet. Chem., 35, 21-43 (1984). J. Crank, Mathematics afDiffusian (Oxford University Press, London, 1956). C. R. Robbins, The Chemical and Physical Behavior of Human Hair (Van Nostrand Reinhold, New York, 1979). Y. K. Kamath, C.J. Dansizer, and H.-D. Weigmann, Maragoni effect in the water wetting of surfactant coated human hair fibers, J. Call. Interface Sci. 102, 164-172 (1984). H.-D. Weigmann and Y. K. Kamath, Modification of human hair through fiber surface treatments: Characterization by wettability, Cosmet, Toiletr., 101, 37-49 (1986). H.-D. Weigmann, Y. K. Kamath, S. B. Ruetsch, P. Busch, and H. Tessman, Characterization of surface deposits on hair fibers, J. Sac. Cosmet. Chem., 41, 379-390 (1990). C. R. Robbins and R. J. Crawford, Cuticle damage and the tensile properties of human hair, J. Sac. Cosmet. Chem., 42, 59-67 (1991).