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In the case of a monomer having a hydroxyl group, the hydroxyl group may be replaced by an acetal group suscep› tible to deprotection with acid, typically ethoxyethoxy, prior 

to polymerization, and the polymerization be followed by deprotection with weak acid and water. Alternatively, the hydroxy group may be replaced by an acetyl, formyl, pivaloyl or similar group prior to polymerization, and the polymeriza- tion be followed by alkaline hydrolysis. 

In a more preferred embodiment, the polymer serving as base resin has further copolymerized therein recurring units ( d) selected from units ( dl) to ( d5) ofindene, acenaphthylene, chromone, coumarin, and norbornadiene, or derivatives thereof, represented by the following formula (6). 

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Herein R$^{25 }$is each independently hydrogen, a C$_{1}$-C$_{30 }$alkyl, haloalkyl, alkoxy, alkanoyl or alkoxycarbonyl group, C$_{6}$-C$_{10 }$ aryl group, halogen, or 1,1,1,3,3,3-hexafluoro-2-propanol group, and W $^{6 }$is methylene, oxygen or sulfur. As used herein, the term "haloalkyl" refers to alkyl in which some or all hydrogen atoms are substituted by halogen. 

Examples of suitable monomers from which recurring units ( dl) to ( d5) of indene, acenaphthylene, chromone, cou› marin, and norbomadiene derivatives are derived are given below. 

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