Photochromic plastic object
AssigneeOptische Werke G. Rodenstock
InventorsClaudia Mann, Manfred Melzig, Udo Weigand
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AssigneeOptische Werke G. Rodenstock
InventorsClaudia Mann, Manfred Melzig, Udo Weigand
Estimating the term…
The invention relates to photochromic plastic objects comprising a plastic material and at least two photochromic pyran derivatives, which are introduced therein and, in each case, have an aryl group, which is linked to the carbon atom adjacent to the pyran oxygen atom and is substituted with at least one group containing at least one nitrogen atom, the longest wavelength absorption maximum of the light-stimulated form of the one pyran derivative lying above 550 nm and the longest wavelength absorption of the light-stimulated form of the other pyran derivative lying below 550 nm and the pyran derivative, absorbing at the shorter wavelength, being selected from 3[H]-naphtho[2,1-b]pyrans and the pyran derivative, absorbing at the longer wavelength, being selected from indeno[2,1-f]naphtho[1,2-b]pyrans or spiro-9-fluoreno[1,2-b]pyrans. The photochromic plastic objects of the present invention are distinguished particularly by a long service life, a good decolorization rate, by the absence of yellowing as well as by a neutral perceived color, it being possible to dispense largely or completely with the use of stabilizers and the like in the inventive plastic objects.
A photochromic plastic object comprising a plastic material and at least two photochromic pyran compounds introduced into said plastic material, wherein each of said photochromic pyran compounds has an aryl group linked to the carbon atom adjacent the pyran oxygen atom, and each said aryl group is substituted with at least one group containing at least one nitrogen atom, one of said photochromic pyran compounds in light stimulated form having a longest wavelength absorption maximum lying above 550 nm and being selected from the group consisting of indeno[2,1-f]naphtho[1,2-b]pyran compounds and spiro-9-fluoreno[1,2-b]pyran compounds, and another of said photochromic pyran compounds in light-stimulated form having a longest wavelength absorption maximum lying below 550 nm and being selected from the group consisting of 3[H]-naphtho[2,1-b]pyran compounds.
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