| abstract |
A compound comprising 0.001 to 100 mole percent of a structural unit of the formula wherein W is -CMe2- or -Se-, R1 is C1-C20 alkyl or aralkyl, R2 to R5 each represents H, C1-C6 alkyl, etc., R6 and R7 each represents H, C1-C6 alkyl, etc., X is O or S, provided that when W is -CMe2-, X is S, and 0 to 99.999 mole percent of a structural unit of the formula wherein Y is H or Me and Z represents alkoxycarbonyl, phenyl, etc. |