536 JOURNAL OF COSMETIC SCIENCE band intensity evaluations, normalized EDF values for each bleaching time are displayed in Tables II and III, where normalized EDF values were calculated using Equation 2. Table II includes normalized cortical EDF values, and Table III contains normalized whole hair tress EDF indices. Normalized Band normalized cm-1 intensity for bleach EDF = 1040 fibers Band normalized cm-1 intensityfor unbleached 1040 fibers (2) where normalized EDF ≥1 for bleached hair, and band normalized 1040 cm−1 refers to indexing the 1040 cm−1 intensity to the 1003, 1080, 1548, and 1650 cm−1 protein bands, as described in the “Raman Spectroscopy of Cross-Sectioned Hair” and “FTIR-ATR of Hair Cross-Sections” sections. Overall, EDF values increased with increasing bleaching time. The cortical EDF values for Raman against FTIR techniques correlate linearly (R2=0.95–0.99), independent of the band chosen for normalization. Similarly, if the 0 and 15 min bleaching Table II Normalized Cortical EDF Ratios Versus Bleaching Time as Indexed from Various Spectroscopic Methods Bleaching time (min) Raman cortexa 1040/1003 cm−1 ATR cortexa 1040/1548 cm−1 Imaging cortexa 1040/1548 cm−1 Imaging cortexb 1040/1650 cm−1 Imaging cortexb 1040/1080 cm−1 0 1.00 1.00 1.00 1.00 1.00 15 2.25 1.34 1.36 1.10 1.68 30 3.04 1.49 1.44 1.14 2.04 45 3.66 1.61 1.69 1.21 2.20 60 4.00 1.83 1.97 1.26 2.23 90 5.03 2.44 2.42 1.32 3.04 120 5.99 3.29 3.72 1.39 3.29 180 6.68 4.27 4.44 1.43 4.04 240 9.19 5.34 5.21 1.50 5.09 a Normalized by band area. b Normalized by band height. Table III Normalized Whole Hair Tress EDF Ratios Versus Bleaching Time as Indexed from the Various Spectroscopic Methods Bleaching time (min) Raman whole fibera 1040/1003 cm−1 ATR whole fibera 1040/1080 cm−1 ATR whole fibera 1040/1548 cm−1 Raman whole fibera 1040/1650 cm−1 Spectrofluorimetry (TRP)b 440/339 nm intensity 0 1.00 1.00 1.00 1.00 1.00 15 1.65 1.23 1.08 1.71 1.26 30 4.49 1.53 1.23 4.19 1.52 45 4.97 2.25 1.53 5.93 1.65 60 6.84 2.89 2.57 8.46 1.93 90 7.93 3.70 3.52 9.79 1.99 120 8.31 4.00 4.06 10.55 2.17 180 8.19 4.35 4.03 10.89 2.18 240 8.34 4.40 4.02 11.74 2.52 a Normalized by band area. b Normalized by band height.

537 CHARACTERIZATION OF BLEACHED HAIR steps are removed (due to small Raman fluorescence artifacts), linear correlations between Raman and FTIR-ATR whole hair fiber EDF analyses are excellent, with R2=0.93–0.98. More importantly, spectral correlations between whole tress and cross-sections analyses are weaker, when judged solely by the magnitudes of scatter plot correlation coefficients (R2=0.60-0.78). In the “FTIR-ATR of Hair Cross-Sections” and “Raman Spectroscopy of Cross-Sectioned Hair” sections, we applied aspect-ratio arguments to justify the use of cross-sections spectra as solely describing chemical changes in the cortex. To complete the rationalization, note that spectra from FTIR chemical imaging of cross-sections were sampled solely from pixels of the hair fiber cortex. Hence, stronger correlations between FTIR imaging and FTIR-ATR/Raman cross-sections spectra, and weaker correlations between FTIR imaging and whole fiber analyses further support the acceptable use of “cortical” when describing the spectral analyses of hair fiber cross-sections. Finally, we have been synonymously referring to the normalized 509 cm−1 band as EDF more accurately, however, the Raman 509/1003 cm−1 band ratio is roughly EDF−1, where increases in cysteic acid are proportional to decreases in cystine (e.g., Figures 11 and 12). Figure 13 looks at the process of cystine bleaching damage through Fick’s laws of diffusion, where a substance is said to follow Fickian diffusion if the normalized solute uptake linearly relates with the square root of process time (24). Figure 13 contains a plot of the process- normalized Raman cysteic acid scattering intensity (1040/1003 cm−1) against the square root of bleaching time. The approximate diffusion coefficient (D) for bleach consumption, as monitored by the conversion of cystine to cysteic acid, was evaluated as 1.1 × 10−8 cm2min−1. The approximate diffusion coefficient was evaluated from the slope of the graph and the average cross-sectional fiber radius (1,24). The linearity of cortical oxidation with the square root of time generally agrees with the visual interpretation displayed by the FTIR micro-spectroscopic spatial maps exhibited in Figure 3. HPDSC ANALYSIS OF BLEACHED HAIR In the HPDSC method for analyzing the state of hair keratin, snippets of hair are soaked in water and then heated through the denaturation temperature in sealed stainless steel crucibles. By thermally insulting the fiber cortex in the wet state rather than the dry state, water plasticization of the cortical matrix separates denaturation and pyrolysis events (6–15). T D probes the plasticity and viscosity of the matrix, whereas ΔH D represents the Figure 13. Diffusion plot for the normalized Raman EDF band height versus square root of bleaching time. SQRT: square root.