14 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS are used to provide conditioning benefits, resulting in increased fiber alignment, thus producing a smoother surface from which to reflect light. This in turn, provides an increase in specular reflection, making the hair appear more lustrous. Cyclomethicones may be used in this application, but the effect is transitory since cyclomethicones will volatilize from the hair. The second, more widely utilized, method is to coat hair with a material of relatively high refractive index, closer to that of the hair cuticle. The reason for this is that incident light is believed to be reflected by the underlying melanin granules. Thus, by coating the fiber with a material whose refractive index is close to that of the hair cuticle, incident light will scatter less as it passes through the various cuticle-cuticle, or cuticle-cortex interfaces. This will result in an increase in specular reflection, making the hair appear to be glossier or more lustrous (27). Thus, minimizing the difference in refractive index between the coating material and the cuticle scales maximizes the increase in apparent luster of the hair (39). The refractive index of dimethicone fluids ranges from 1.3970 for a 5-cst fluid to 1.4035 for fluids of 5,000 cst viscosity and higher, as shown in Table V. The mechanism by which dimethyl fluids function as luster-enhancing agents is through increasing fiber alignment, providing a smoother surface from which to reflect incident light as men- tioned above. Phenyltrimethicone, a fluid commonly used for shine enhancement in hair gloss sprays and cuticle coat products is characterized by a refractive index of 1.459- 1.461. Phenethyl or styryl modification of the siloxysilicate resin was found to yield a fluid of refractive index of 1.505, substantially higher (and much closer to the refractive index of the hair cuticle) than that of other silicone fluids. It was therefore envisaged that this fluid would be beneficial in hair shine enhancement applications. The styryl-modified siloxysilicate resin was formulated into a cuticle coat conditioning product as shown in Formulation 2 listed in Appendix A. This composition was used in luster evaluations on Caucasian and Oriental hair types, being compared to tresses treated with 1) a commercial shine spray comprising dimethicone gum, cyclomethicone, and several organic oils, 2) a commercial cuticle coat containing dimethicone and phenyltrimethicone, and 3) a protein-based shine-enhancer product. The results of luster evaluations are presented in Table VI. It can be seen that the commercial cuticle coat product provided no improvement in shine as observed by the panel. The commercial shine spray product offered a minimal improvement in shine of 6% and 14% for the Oriental and Caucasian hair types, respectively, as compared to the untreated controls. The protein-based shine-enhancer composition actually reduced hair luster by approxi- mately 10% according to the panelists. The cuticle coat formulation containing the phenethyl-modified siloxysilicate, however, was found to produce a dramatic increase in apparent luster for both hair types evaluated. The hair treated with the composition Table V Refractive Index of Various Silicones Material nD (25øC) PDMS (350 cst) 1.40' Phenyltrimethicone 1.460 Phenethyl siloxysilicate 1.505 * Refractive index of dimethyl fluids ranges from 1.3970 for a 5-cst fluid to 1.4035 for fluids of 5,000 cst viscosity and higher.

ORGANOFUNCTIONALIZED SILICONE RESINS 15 Table VI Results of Luster Evaluations on Caucasian and Oriental Hair Types Treatment Caucasian Oriental Untreated control 2.9 3.0 Commercial shine spray 3.3 3.2 Protein shine enhancer 2.6 -- Commercial cuticle coat 3.0 Cuticle coat, Formulation 2 3.5 4.5 containing the styryl-modified resin consistently rated higher in shine evaluations than the other products, with averages of 21 and 50 percent higher ratings for Caucasian and Oriental hair types, respectively, as compared to the untreated controls. SUBSTANTIVITY The last series of materials evaluated in this study were the ester-modified siloxysilicate resins. Table II lists some of the typical acids and alcohols utilized in preparing the esters that were subsequently grafted onto the siloxysiticate resins. Combinations involving saturated alcohols and unsaturated organic acids resulted in stable products that were not found to offer any performance benefits. Combinations involving short-chain unsaturat- ed alcohols (e.g., allyl alcohol) and saturated organic acids resulted in unstable products. Materials obtained from the reaction of a saturated acid with a long-chain, branched, unsaturated alcohol were characterized as being stable and providing some interesting performance benefits. Based on the data above, trimethylolpropane monoallyl ether (TMPMAE) became the alcohol of choice, and this material was reacted with linear and branched acids of varying chain lengths. The melting point and physical forms of several siloxysilicate resins modified with the resulting esters are listed in Table VII below. During cursory evaluations with these compounds, it was observed that the ester- modified resins were somewhat substantive to skin. To further evaluate substantivity properties of the various ester-functional siloxysilicates, a modified ASTM spray test method was utilized. The ester-functional resins showed enhanced substantivity and water resistance in this evaluation as compared to the other fluids tested, as demon- strated in Figure 6. The low-viscosity dimethicone fluid was completely removed after one spray cycle. The organic ester and the unmodified silicone resin were both com- pletely removed after four cycles, while the C•2 and C•6 ester-modified resins were present at 15% and 25%, respectively, after six wash cycles. The C•s isostearyl- functional resin was slightly more substantive during the first few spray cycles, but by Table VII Melting Points and Physical Forms of Siloxysilicate Resins Modified With Various Organic Esters Acid chain length Melting point (øC) Physical form Lauric (C• 2) - 25 Liquid Myristic (C•4) + 5 Liquid Palmitic (C•6) + 20 Liquid Stearic (C•8) + 35 Hard wax Isostearic (C• 8) -40 Liquid