content_image/889153.jpg content_image/889154.jpg content_image/889155.jpg content_image/889160.jpg
<img src='content_image/889153.jpg'>

<img src='content_image/889154.jpg'>

In formulae (Alla) to (AIIc), R$_{1}$c represents a hydrogen atom, a methyl group, a trifluoromethyl group or ahydroxym› ethyl group. 

R$_{2}$c, R$_{3}$c and R$_{4}$c respectively have the same meaning with R$_{2}$c, R$_{3}$c and R$_{4}$c in formulae (VIIa) to (VIIc). 

The specific examples of repeating units having a hydroxyl group or a cyano group are shown below but the invention is not restricted thereto. 

<img src='content_image/889155.jpg'>

-continued 

<img src='content_image/889160.jpg'>

Repeating unit (b) may be a repeating unit having a lactone structure as the polar group. 

