284 JOURNAL OF COSMETIC SCIENCE incomplete shampooing induce a formation of pores in hair fiber or roughness on hair surface. If their sizes are larger than light wavelength, they behave as diffuse reflection sources which result in dull or colorless dry appearance. Combination of solvents and organic acids under a low pH condition were reported as a hair treatment system to reduce such diffuse reflection sources. Penetration of the acids is accelerated in the system to swell hair fiber protein resulting in reduction of inner pores (4,5). Addition- ally, re-adhesion effect of cuticle lift-up part and removal effect of scam are also reported to regain the original optical natures of hair (6). In this paper, a novel approach to develop hair optical properties is attempted by modification of hair surface. If an asperity of hair surface is finer than light wavelength, the structure doesn't work as a light drying, the color was measured as 6 parts on hair tress to calculate the mean value. This series of operation was repeated for 30 cycles. Deference from the original color of untreated tress (cycle = 0) was evaluated as a color change of each cycle. EVALUATION OF DYED HUMAN HEAD Color change of dyed hair was evaluated by half head comparing method of the control and the test systems. Originally brown color hair American women were evenly dyed using commercial red oxidation dye. Colors of 20 parts for both sides were measured as the original color value before the treatment. Shampoo and conditioner treatment, and color measurement after each treatment was performed cyclically for 12 times. The treatment process was performed by a beautician. OBSERVATION OF HAIR FIBER SURFACE Atomic Force Microscopy (Nano Scope □!Multi Mode AFM, Digital Instrument Inc., Tapping Mode measurement) was used for measurement of fine structure size on hair fiber surface. Element distribution on the structure was evaluated using Field Emission Type Scanning Electron Microscopy attached with Energy Dispersive Spectroscopy (FE- SEM-EDS/JSM5200, JEOL, lKeV) with no courting on surface. REFLECTION MEASUREMENT ON HAIR FIBER SURF ACE Reflection intensity dependence on light wavelength was measured using Goniopho- tometer (GP-200, Murakami Color Research Laboratory). Light source (halogen lamp parallel light) was isolated into 3 kinds of monochromatic light using narrow-band interference filter (center wavelength = 410 nm, = 5 50 nm, 690 nm / FWHM = 10 nm, Edmund Optics Inc.). Aligned 10 pieces of hair fiber on a stage were irradiated at 45 degree of incident angle from root side to tip side of hair fiber. Reflection was detected at 45 ± 15 degree. In ± 15 degree of detecting range, maximum peak value was evaluated as surface specular reflection. RESULTS CHROMA CHANGE AND SURFACE OBSERVATION OF HAIR TRESS Chroma changes in the treatment cycles of the control and the test systems were showed

2006 TRI/PRINCETON CONFERENCE 285 in Figure 1. Continuous chroma enhancement and subsequent saturation were observed in the treatment cycles of the test system. Visually-apparent color enhancement was also confirmed simultaneously. In contrast, slight chroma enhancing at first several cycles and getting back to the original level after further cycles were observed in the control system treatment, and no change of color was also visually confirmed. AFM observations of hair fiber surface sampled at each cycle showed a relation between fine structure formation on the surface and chroma enhancement (Figure 2). In the case of the control system, asperity appearance in the first several cycles and its flatting out after further treatments were observed. This process is considered as a result of adsorption saturation of fatty alcohol, the major ingredient of conditioners, on hair fiber surface, because no change on surfaces was observed with only the control shampoo. However, continuous growing of the asperity was observed by the test system treatments. Element analyses on the hair surface after 20 cycles of the test system treatment showed a web like pattern of silicon with the similar scale in size of the structure (Figure 3). The result indicates an inhibition of fatty alcohol saturation on hair surface by amino-silicone. Deposition pattern control of amino-silicone is thus supported to be important point of the phe- nomenon. LIGHT REFLECTION ON THE HAIR FIBER SURFACE TREATED BY THE TEST SYSTEM Intensities of surface specular reflection in the test system treatment cycles are shown in QJ u u 2.0 1.5 1.0 0.5 0 0 I t (Cycle 0) Test system Control system 10 20 30 Treatment cycles I I I + � Control system Test system (Cycle 30) Figure 1. Chroma change in the shampoo and conditioner treatment cycles.