A series of block copolymers from hydroxyl-terminated cellulose triacetate (HCTA) and cellulose triacetate (CTA) with polyethylene glycol (PEG) were prepared. To activate terminal acid groups in the polyethylene glycols, acid groups were first converted to the acetyl groups with chlorination reaction. In the second series, the cellulose triacetate, having fully substituted acetate groups, was hydrolyzed by the acid catalyst method by using acetic acid and small percentages of water. Then cellulose derivatives containing 4-(4-nitrophenylazo)-1-naphthol (Magneson 11) as a chromophore and long hydrocarbon side chains were prepared. The compound 4'-bromobutoxy-4-(4-nitrophenylazo)naphthalene was first synthesized from 4-(4-nitrophenylazo)-1 -naphthol and 1,4-dibromobutane. The alkylated chromophore reacted with prepared cellulosic and oligocellulosic copolymers in the solution of dimethyl sulfoxide to produce cellulose ethers having the desired chromophore. Polymers containing a mixture of alkyl side chains were also prepared by the addition of 1-bromododecane to the reaction mixture. The above method was used for the preparation of (dodecyl) [4'-butoxy-4-(4-nitrophenylazo)naphthalene] (CTA-co-PEG2000) and (dodecyl) [4'-butoxy-4-(4-nitrophenylazo)naphthalene] (HCTA-co-PEG2000). The structure of products was determined by FTIR, H-1-NMR spectroscopy, GPC, and the intrinsic viscosity measurement. (C) 2004 Wiley Periodicals, Inc.