Light bleaching properties

Spirooxazines (NISO) have UV activation properties and thermal bleaching properties that are convenient for eyewear applications. A plastic photochromic lens must have several features, such as (1) ultraviolet energy protection, (2) comfortably lightweight, and (3) tint from a fashionably light tint to a functionally darker tinted sun lens. 45... 

The light fastness of the vic-triazole 11.17 on nylon is 4-5 as on cotton this is significantly superior to that of the DAST derivatives. Unlike the DAST types, the vic-triazole is also stable towards a sodium chlorite bleach. Applied to nylon in combination with sodium chlorite, compound 11.17 can give exceptionally high whiteness and excellent fastness properties. 

P.O.5 is in high demand in the field of the textile printing. As far as most of the relevant fastness properties are concerned, P.O.5 performs less well than the somewhat yellower and much more expensive perinone pigment P.O.43. Compared to the somewhat yellower P.O.34, however, its fastness to light is superior. 1/3 SD P.O.5 samples equal step 7 on the Blue Scale, as opposed to step 5-6 reached by P.O.34. In other respects, such as fastness to dry-cleaning with perchloroethylene or petrolether, to laundering with peroxide bleach or alkali, P.O.5 performs less well than P.O.34. 

In spin dyed secondary acetate threads, fibers, and films, P.B1.25 exhibits good textile fastness properties the only problem is a certain lack of fastness to bleaching with sodium hypochlorite (Sec. 1.6.2.4). Its fastness to light in 0.1% spin dyed specimens equals step 3-4 on the Blue Scale, while 1% samples equal step 5. 

The coloration and bleaching processes consist of irradiation with UV light and a 632.8-nm laser, respectively. After five hundred written-erased cycles on the photochromic disk sample, there was no change that could be observed in the photosensitivity and other properties of the disk. The sample was stored at ambient conditions for over 5 years with its optical properties well preserved. 

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