Chemistry Reference
In-Depth Information
a series of polymers containing
dyes with large differences in the second order transition temperature
were compared [
225
]. Particular emphasis was placed on the relationship between photo-isomerization,
T
g
of the polymers, and their molecular structure. As a result, it was shown that light-induced nonpolar
orientation in very high
azo
T
g
up to 350
C) can take place even at room temperature.
The polymers used in one of these studies can be illustrated as follows [
225
]:
T
g
polyimides (
O
O
R
N
N
n
O
O
N
O
2
N
N
N
O
O
R
N
N
n
O
O
N
N
N
NO
2
where R
ΒΌ
(CF
3
)
2
-C
<
in one polymer and -COO-(CH
2
)
2
-COO- in another.
