The invention pertains to an isosorbide derivative having at least one polymerizable group, characterized in that the isosorbide derivative further comprises at least one photo-convertible group for adjusting the helical twisting power of the isosorbide derivative. According to a preferred embodiment the isosorbide has the formula
1
wherein
A stands for a bond or a p-phenylene group;
B and B′ are independently O—(CH
2
)
o
O—CO—CR′═CH
2
, o being 2-12 and R′ being H or CH
3
;
P stands for a CH
2
or a C═O group;
Q and Q′ are independently selected from H, C1-C3 alkyl, C1-C3 alkoxy, halogen, and CN;
n is an integer from 1 to 3; and
m is an integer from 0 to 2.
The invention pertains to a phenylethanediol derivative having at least one polymerizable group, characterized in that the phenylethanediol derivative further comprises at least one photo-convertible group for adjusting the helical twisting power of the phenylethanediol derivative. According to a preferred embodiment the phenylethanediol has the formula
wherein A stands for a bond or a p-phenylene group;
B and B′ are independently (O)
p
—C
o
H
2o
—O—CO—CR′═CH
2
, o being 2-12, p being 0 or 1, and R′ being H or CH
3
;
P stands for a CH
2
or a C═O group; Q and Q′ are independently selected from H, C1-C3 alkyl, C1-C3 alkoxy, halogen, and CN; n is an integer from 1 to 3; and
m is an integer from 0 to 2; and:
wherein A stands for a bond or a p-phenylene group;
B is (O)
p
—C
o
H
2o
—O—CO—CR′═CH
2
, o being 2-12, p is 1, and R′ being H or CH
3
;
P stands for a CH
2
or a C═O group; Q is selected from H, C1-C3 alkyl, C1-C3 alkoxy, halogen, and CN; and m is an integer from 0 to 2.