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首页> 外文期刊>Applied Magnetic Resonance >Measurement of the nuclear spin diffusion coefficient in organic glasses doped with paramagnetic centers: Orthoterphenyl and polymeric glasses
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Measurement of the nuclear spin diffusion coefficient in organic glasses doped with paramagnetic centers: Orthoterphenyl and polymeric glasses

机译：掺杂顺磁性中心的有机玻璃中核自旋扩散系数的测量：邻三苯基和聚合物玻璃

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We have recently developed a method Of Studying spin diffusion coefficients by doping the materials with Paramagnetic centers and measuring the nuclear relaxation in a tilted rotating frame. Using this method, we measure here the spin diffusion coefficient of orthoterphenyl, a molecular organic glass, and of three polymer glasses: poly(4-vinylpyridine), poly(vinylacetate) and poly(methyl methacrylate). We explore a possible dependence of the measured orthoterphenyl spin diffusion coefficient on the electronic relaxation time and concentration of the Paramagnetic centers. We conclude that the experiments can be performed at higher concentrations than previously thought. We also show that our method applies to polymers in the glassy state if one works at Sufficiently small tilt angle, in spite of a short value of T-1p. We had anticipated that the distribution of proton pairs in these materials precludes the standard dependence of the spin diffusion coefficient on the proton density and free induction decay characteristic decay time. Our results fully confirm such expectation.
机译：我们最近开发了一种研究自旋扩散系数的方法，该方法通过在材料中掺杂顺磁性中心并测量倾斜旋转框架中的核弛豫。使用这种方法，我们在这里测量邻三苯基，一种分子有机玻璃和三种聚合物玻璃的自旋扩散系数：聚（4-乙烯基吡啶），聚（乙酸乙烯酯）和聚（甲基丙烯酸甲酯）。我们探讨了测得的邻三苯基自旋扩散系数对电子弛豫时间和顺磁性中心浓度的可能依赖性。我们得出结论，可以在比以前认为的更高的浓度下进行实验。我们还表明，即使T-1p值短，只要倾斜角度足够小，我们的方法也适用于玻璃态聚合物。我们已经预料到，质子对在这些材料中的分布排除了自旋扩散系数对质子密度和自由感应衰减特性衰减时间的标准依赖性。我们的结果充分证实了这种期望。

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