A series of thermotropic side chain liquid crystalline poly ω (4' methoxy 4 azophenyloxy)alkanoyl methacrylates (PMAAZO n

n =2

3

4

5

6) were prepared by the reaction of potassium methacrylate and 4 methoxy 4' (1 bromoalkoxy)azobenzene

then free radical polymerization in THF solution.Their structures were verified by 1H

13C-NMR and IR spectra.The number average molecular weight (MW) of PMAAZO n were around 20

000

thus the effects of M W on the liquid crystalline (LC) properties were negligible.The LC behaviors of the polymers obtained were examined by DSC and optical polarizing microscope.Only one nenatic state for PMAAZOn

(n=2

3 and two LC states:one smectic and one nematic state for the polymers of n=5 and 6 were observed.As spacer length increased

glass transition temperature decreased.On the curves of △H and △S against spacer length

the lowest values appeared at n=3.The lowest stability of LC state was probably the result of odd-even effect and low decoupling.The odd-even effect on TNI of PMAAZOn was observed

and explained based on the placement of the mesogenic groups on relation to the polymer backbone.The physical aging process of the polymers would increase their TNI and decrease △HNI.