Radiation-sensitive mixture and use thereof

A radiation-sensitive mixture which is suitable for preparing a polyimide, a polyisoindoloquinazolinedione, a polyoxazinedione, a polyquinazolinedione or a polyquinazolone and which on irradiation with actinic light undergoes solubility differentiation, conprising of

• (a) one or more precursors having structural elements of the general formula (I) ##STR14## where, A is --O--, --NH-- or a single bond,
• Q is an aromatic tetravalent radical, or a radical which contains two bivalent aromatic radicals linked by a bridging group, wherein two at a time of the valences are adjacent to each other,
• B.sup.1 is --O--, or --NR.sup.4 --,
• B.sup.2 is --NH--CO--NH--, --NH--CO--O--, --NH--CO--or a single bond,
• R.sup.1 is a readily hydrogen-donating radical,
• R.sup.2 is a bivalent aliphatic or aromatic radical or a single bond,
• R.sup.3 is a bivalent aliphatic, cycloaliphatic, aromatic or heterocyclic radical which may be halogen-substituted and
• R.sup.4 is H or straight-chain or branched alkyl which may be halogen-substituted,
• with the proviso that the readily hydrogen-donating radical R.sup.1 is a radical selected from the group consisting of isoalkyls, aminoisoalkyls, and groups of the following general formulae:
• ##STR15## where n=2 or 3 and
• R.sup.5 is alkyl, aryl, halogen-substituted alkyl or halogen- substituted aryl,
• (b) one or more aryl-containing carbonyl compounds which when excited by UV radiation are capable of hydrogen abstraction, and optionally
• (c) one or more substances selected from the group consisting of a photoinitiator, a photosensitizer, a (leuco)dye and an aliphatic ketone.