Shin W S, Li X F, Schwartz B, Wunder S L, Baran G R
Department of Chemistry, Temple University, Philadelphia, PA.
Dent Mater. 1993 Sep;9(5):317-24. doi: 10.1016/0109-5641(93)90050-z.
FT-IR spectroscopy has traditionally been used to determine the degree of conversion of dental resins. FT-Raman scattering provided an alternate method of obtaining degrees of conversion for these systems and was particularly useful for measuring spectra of materials without any sample preparation. Raman and FT-Raman spectroscopy gave identical results, but the latter technique was preferred for the highly fluorescent samples often encountered in commercial composites. Linear calibration curves were obtained for the aromatic mixtures Bis-GMA/TEGDMA and Bisphenol-A/TEGDMA using C = C/phi, and for the wholly aliphatic mixture EGDMA/EGDA using C = C/C = O, over a wide range of mole ratios. If both the mole and intensity ratios [C = C/phi or C = C/C = O] were known for an uncured dental resin, then the degrees of conversion could be obtained for the cured materials using Raman spectroscopy. However, if the mole ratios for the uncured resin were unknown, then the degree of conversion depended on the calibration curve, since the Raman scattering cross section of the vibrational modes depended on the molecules to which they were attached.
傅里叶变换红外光谱法传统上用于测定牙科树脂的固化程度。傅里叶变换拉曼散射提供了一种获取这些体系固化程度的替代方法，并且对于测量无需任何样品制备的材料光谱特别有用。拉曼光谱和傅里叶变换拉曼光谱给出了相同的结果，但后一种技术更适用于商业复合材料中经常遇到的高荧光样品。使用C = C/phi为芳香族混合物双酚A缩水甘油醚/三乙二醇二甲基丙烯酸酯（Bis - GMA/TEGDMA）和双酚A/三乙二醇二甲基丙烯酸酯（Bisphenol - A/TEGDMA），以及使用C = C/C = O为全脂肪族混合物乙二醇二甲基丙烯酸酯/乙二醇二丙烯酸酯（EGDMA/EGDA），在很宽的摩尔比范围内获得了线性校准曲线。如果对于未固化的牙科树脂，摩尔比和强度比[C = C/phi或C = C/C = O]都已知，那么使用拉曼光谱法就可以获得固化材料的固化程度。然而，如果未固化树脂的摩尔比未知，那么固化程度就取决于校准曲线，因为振动模式的拉曼散射截面取决于它们所附着的分子。
