The present invention relates to a method of preparing a solution of a polymer comprising recurring azole units, which comprises dissolving a sufficiently dried polymer comprising recurring azole units of the formula ##STR1##

where the radicals Ar, Ar¹ and Ar² are tetravalent, divalent or trivalent aromatic or heteroaromatic groups and the radicals X, which are identical within a repeating unit, are each an oxygen atom, a sulfur atom or an amino group bearing a hydrogen atom, a group having 1-20 carbon atoms, preferably a branched or unbranched alkyl or alkoxy group, or an aryl group as further radical, in N,N-dimethylacetamide having a sufficiently low water content at a temperature above room temperature under an inert gas atmosphere, wherein a sufficiently dried polymer comprising recurring azole units of the formula (1) or (2) of which 90% by weight based on the total weight of the polymer comprising recurring azole units has a particle size of less than 1 mm is used.