The compatibility of cellulose diacetate with triacetin and esters of butylcellosolve with dicarboxylic aliphatic acids was studied for a wide range of compositions. The glass transition temperature Tg, the dielectric relaxation activation energy and the tensile creep for the plasticized systems were determined. It is shown that when the esters are added to triacetin in small amounts, which correspond to the formation of compatible systems, the plasticizing effect is enhanced and the molecular mobility of the system components is improved. © 1995 Blackie Academic & Professional.