研究了β-二酮类化合物二苯甲酰甲烷、苯甲酰丙酮、对苯二甲酰乙酸乙酯的光稳定行为,在β-二酮类化合物的溶液中存在着烯醇式和酮式平衡。当以紫外光进行辐照时,烯醇式异构体不断减少,酮式的含量则不断增多。由于这些化合物有不同的互变异构化过程以及不同的氢键形成能力,因此,它们对高聚物有着不同的稳定化能力。我们提出的二苯甲酰甲烷的光稳定机理,不同于Otterstedt提出的机理。新的统一的光稳定机理尚待进一步深入研究. The photostabilistic behavior of β-diketones such as dibenzoylmethane, benzoylacetone and ethyl-p-phenylacetoacetate was studied. The enantiomeric and keto balance. When irradiated with UV light, enol isomers continue to decrease, while the amount of ketones is increasing. Because of their different tautomerisation and their ability to form hydrogen bonds, these compounds have different stabilizing properties for polymers. Our proposed photostabilizing mechanism of dibenzoylmethane is different from that proposed by Otterstedt. The new unified mechanism of light stability remains to be further studied.