Patent ID: 6306316
Filing Date: 2001-10-23
Classification: C08K,G02B

Abstract:
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.