FOURIER TRANSFORM INFRARED SPECTROSCOPY OF HAIR 63 with the root ends glued to the tabs. The tresses were shampooed before treatment or weathering. ii. For accelerated weathering an Atlas Weather-Ometer (Atlas Electric Device Co., Chicago, Ill.), model 65-WRC, was used. This instrument was equipped with a 6000- watt xenon arc lamp, with borosilicate filters designed to approximate the spectral distribution of summer sunlight. The unit had temperature and humidity controlk and water spray capability during the dark cycle. iii. Spectra were obtained on a Digilab FTS-10M spectrometer. The instrument was purged with nitrogen and equipped with a hot wire source and a triglycine sulfate detector. Some spectra were obtained with a globar source and a liquid nitrogen-cooled mercury cadmium telluride detector. Spectra were collected at 4 cm-• resolution using boxcar apodization and coadding 1000 scans. The sampling device was a. high pressure diamond anvil cell (High Pressure Diamond Optics, Tuscon, Arizona) and is more fully described elsewhere (l 1). Basically, the cell consisted of two type-II diamonds mounted in pistons which were squeezed together by a spring acting on a lever arm. Hair fibers were held in place on one diamond (about 1.5 mm in diameter) with the aid of two-sided tape placed at the sides of the diamond. The cell was closed and pressure cycled a few times to flatten the hair fibers and completely cover the diamond windows. The cell was centere.d in the IR beam at the focal point of a 6 X beam condenser in the sample chamber and the pressure was returned to zero by releasing the spring tension. When the variability of treatments and the precision of the method was evaluated, three or four fibers were used to cover the window without overlapping. For the weathering studies, 9-11 fibers were stretched across the diamonds for each analysis. BLEACHING AND WAVING PROCEDURES To test the precision of the analytical method and the reproducibility of treatments, brown hair was given one of three mild treatments. Each treatment was performed in triplicate for a total of nine tresses. Triplicate FTIR analyses were performed on each tress. The treatments were as follows: i. Bleaching (Samples A). The bleach solution was prepared by mixing a 6% hydrogen peroxide solution with an equal volume of a 10% urea, 3% glycerine, 7% sodium chloride, and 12% concentrated ammonium hydroxide solution in water. A 2-gram hair tress was soaked in 10 mL of this solution for 30 minutes at 32øC with mild agitation. The tresses were rinsed for 5 mintues in running tap water at 30-35øC and towel blotted. They were then shampooed, blotted, and combed straight. In one series of experiments we exposed tresses to bleaching of different intensities. Quarter and half strength bleaching was done by appropriate dilutions of the above solution, while double bleaching was done by subjecting tresses to two consecutive bleachings as outlined above. ii. Thioglycollate Waving (Samples B). The tresses were shampooed and then rolled on 3/4-inch rollers they were saturated with commercial thioglycollate waving lotion for 20 minutes. After rinsing with water for two minutes, the curls were saturated with neutralizer, left for two minutes, and rinsed with warm tap water.

64 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS iii. Bisu/fite Waving (Samples C). The tresses were shampooed and rinsed, then set on 3/4-inch rollers and saturated with commercial bisulfite waving lotion. The lotion was left on for 60 minutes at 32øC. The tress was rinsed, removed from the rollers, and the neutralizer applied. After 3 minutes, the hair was rinsed and dried. WEATHERING PROCEDURES i. The hair used in all the weathering studies and some of the waving and bleaching studies was thoroughly cleaned prior to use. Approximately 50 g of loosely bundled hair was extracted in a Soxhlet apparatus for 14 hours with 300 mL of anhydrous ether, and then extracted for seven hours with 300 mL of absolute ethanol. After evaporation of the solvent from hair by air drying, the hair was washed in three changes (500 mL each) of distilled water. It was then immersed in two changes of 0.001 N HC1 (500 mL each) for two hours, and finally soaked in large volumes of distilled water until the pH of the rinse water was above 5.0. The hair was air dried and conditioned at 22øC and 65% RH before use. Hair tresses were mounted in the Weather-Ometer on metal holders. Only the bottom halves of the tresses were exposed to radiation the top halves were shielded with aluminum foil. The level of irradiation was constant. The black-body temperature on the tresses was 65øC. The light was cycled at 3.7 hours of exposure and 1 hour of darkness while the relative humidity was 64% during the light cycle and 92% in the dark cycle. Samples were exposed for two- and four-week periods. if. Outdoor weathering was accomplished by mounting the tresses as in the Weather- Ometer. Tresses were exposed to the outdoor environment for 12 weeks in Rockville, Maryland, from the beginning of July through September. Some of the tresses were wetted out daily. iii. Some of the hair samples used for the weathering studies were permanently waved or bleached before exposure. The following procedures were used: The tresses were immersed for 20 minutes at room temperature in 1:1 v/v Toni © regular strength waving lotion and distilled water. The waving lotion was used at a 20:1 bath ratio, i.e., 20 mL solution (after dilution) per gram of hair. Tresses were rinsed for 30 seconds under running, tepid (30-35øC) tap water and blotted with cloth towels. Tresses were immersed for 12 minutes in a neutralizer consisting of 0.75 N hydrogen peroxide, 0.04% phenacetin, and 0.0045 M sodium stannate adjusted to pH 3.5-4.0 with phosphoric acid. A 20:1 bath ratio was used with agitation every 2-3 minutes. The tresses were rinsed as before. The bleaching method was identical to that described above except that one-gram tresses were used. RESULTS ASSIGNMENT OF ABSORPTION BANDS Typical diamond cell spectra of virgin hair and once-bleached hair are shown in Figure 2. In the bleached hair spectrum (B), a sharp band is found at 1042 cm-•, as well as a shoulder on the low frequency side of the 1231 cm -• protein band. The band at