METHOD OF PRODUCING PHOTOCHROMIC MATERIAL BASED ON POLYVINYL ALCOHOL AND PHOSPHORIC-TUNGSTIC ACID Russian patent published in 2012 - IPC G03C1/72 

FIELD: physics.

SUBSTANCE: method of producing photochromic material based on polyvinyl alcohol and phosphoric-tungstic acid involves preparation of an aqueous solution based on polyvinyl alcohol and phosphoric-tungstic acid and forming a film of said material on a substrate from said solution. The prepared aqueous solution of polyvinyl alcohol and phosphoric-tungstic acid contains 10-40 wt % phosphoric-tungstic acid with respect to polyvinyl alcohol. The obtained solution is then cooled to temperature 5-10°C. Glutaric aldehyde is then added to the obtained solution in amount of 5-30 wt % with respect to polyvinyl alcohol. The solution is then deposited onto a substrate and dried at temperature 20-25°C for 24 hours.

EFFECT: obtaining photochromic material based on polyvinyl alcohol and phosphoric-tungstic acid, which is resistant to water and is characterised by high degree of photo-induced colouring.

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