High pressure studies on spiropyrans
High pressure studies on spiropyrans
复制标题
螺吡喃的高压研究
DOI：
10.1063/1.431759
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发表时间：
1975
期刊：
影响因子：
--
通讯作者：
H. G. Drickamer
中科院分区：
文献类型：
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作者：
D. Wilson;H. G. Drickamer
对两种螺吡喃在聚苯乙烯（PS）和聚甲基丙烯酸甲酯（PMMA）薄膜中的溶解态进行了高压光学测量。进行了三种类型的研究。(1)在30-140 kbar的压力区域中，我们观察到压力诱导的着色（压致变色），其与时间、压力施加速率或照射无关。证据支持无色和有色基态之间的直接热跃迁。在转变中涉及的体积变化为0.5-1.5 cm 3/mol的数量级。(2)在8-40 kbar的压力范围内，表明压力急剧降低了光致变色过程的效率。这个过程通过无色分子的三重态进行。随着压力的增加，三重态的能量相对于激发的单重态增加，这降低了系统间交叉的可能性，从而降低了有色物质的形成。(3)在0-10 kbar的压力范围内，热漂白的速率为100%~ 200%。
High pressure optical measurements have been made on two spiropyrans dissolved in films of polystyrene (PS) and polymethyl methacrylate (PMMA). Three types of studies were made. (1) In the pressure region 30–140 kbars we observed pressure induced coloration (piezochromism) which was independent of time, rate of pressure application, or irradiation. The evidence favors a direct thermal transition between the uncolored and colored ground states. The volume change involved in the transition is of the order of 0.5–1.5 cm3/mol. (2) In the pressure range 8–40 kbars, it was demonstrated that pressure drastically reduced the efficienty of the photochromic process. This process proceeds via a triplet state of the uncolored molecule. With increasing pressure the energy of a triplet state increases with respect to the excited singlet state, which reduces the probability of intersystem crossing and therefore of formation of the colored species. (3) In the pressure range 0–10 kbars the rates of thermal bleaching were ...