Modulating Photochemical Properties to Enhance the Stability of Electronically Dimmable Eye Protection Devices

The study evaluates compatibility of stabilizers with dye doped liquid crystal (LC) scaffolds that are used in electronically dimmable materials. The photodegradation of the materials was investigated and suitable stabilizers were evaluated to slow the degradation process. Various types of benzotriazole-based stabilizers were evaluated for stabilizing the liquid crystals. Based on spin trapping experiments, radicals generated upon UV exposure is likely responsible for the degradation of the system. The radical generation is competitively inhibited by the addition of stabilizers. Abbreviations: LC, liquid crystal; STB, stabilizers

3H-Naphtho[2,1-b]pyrans as Photochromic Dichroic Dyes and Optical Articles Containing Them

A naphthopyran compound represented by the formula (I): wherein: n1, n2, p, q is an integer comprised from 0 to 5 inclusive; m is an integer comprised from 0 to 4 inclusive; R1 and R2 represent a group selected from halogen, -Ra, -OH, -ORa, - SH, -SRa, -NH2, -NRaRa1, -NRbRc, -CO-Ra, and -CO2Ra1, wherein Ra, Ra1, Rb and Rc, are as defined in the description ; R3 represents a group selected from halogen, -Ra, -OH, -ORa, -SH, -SRa, -NH2, and -NraRa1; R4 represents a group selected from halogen, -Ra, -OH, -ORa, -SH, -SRa, -NH2, -NRaRa1, -CO-Ra, and -CO2Ra1; R5 represents a group selected from: o halogen, -Ra, -OH, -ORa, -SH, -SRa, -NH2, and -NRaRa1, wherein Ra and Ra1 are as defined hereinbefore, o or when q is equal to 2, then two R5 together represent further a group -O-(CH2)q1-O- wherein ql represents an integer comprised from 1 to 3 inclusive