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.