STUDIES ON THE FLUORESCENT BRIGHTENING PROPERTIES OF SYNTHETIC FIBERS: (I) MEASURING METHODS OF FLUORESCENCE AND THE FLUORESCENT PROPERTIES OF VINYLON

The peculiar behavior and physical state of fluorescent dyes on Vinylon (polyvinyl alcohol fiber) have been mainly investigated on the relationship between fluorescence and amount of dye adsorption on the fiber. A heat-treated polyvinyl alcohol fiber was formalized under various conditions of reaction. As to fluorescent dyes, triazylstilbene, benzoxazol and coumarin derivatives were used. Generally, fluorescence and critical quenching concentration (amount of dye adsorption to occur quenching) on Vinylon dyed with stilbene derivatives decrease as formalization proceeds. In case of Vinylon formalized in sodium sulfate bath, fluorescence is small and the point of critical quenching concentration occurs at the smaller amount of dye adsorption compared with Vinylon in blank bath. On the other hand, fluorescence and critical quenching concentration on Vinylon dyed with oxazol and coumarin derivatives increase as formalization proceeds and the amount are almost unrelated to the conditions of formalization. Such behaviors seem to be related with the physical state of fluorescent dyes on Vinylon and they can be explained from the changes in the loss percentage of energy caused by collision between the excited fluorescent dye molecules, in the fiber.