A photochromic polymer comprising at least two photochromic moieties linked by a straight or branched chain polymer selected from the group consisting of poly(C2 to C4 alkylene oxide), poly[C
1
to C
10
alkoxy substituted (C
2
to C
4
alkylene oxide)] and poly[C
1
to C-
15
acyloxy substituted (C
2
to C
4
alkylene oxide)].