Abstract: Poly-N-vinylcarbazole containing impurities is purified by a process in which the poly-N-vinylcarbazole to be purified is treated in a suitable apparatus at from 20.degree. to 150.degree. C. with an extracting agent.

Abstract: Novel photopolymerizable recording materials suitable in particular for producing photoresist layers and lithographic printing plates are composed of one or more photopolymerizable, olefinically unsaturated organic compounds, optionally a polymeric binder, a photopolymerization initiator, a color-forming system composed of a color former and a photooxidant, a certain benzotriazole compound as a sensitizer and optionally further additive and/or auxiliary substances.

Abstract: Novel photopolymerizable recording materials suitable in particular for producing photoresist layers and lithographic printing plates are composed of one or more photopolymerizable, olefinically unsaturated organic compounds, optionally a polymeric binder, a photopolymerization initiator, a color-forming system composed of a color former and a photooxidant, a certain 4-phenylpyridine as sensitizer and optionally further additive and/or auxiliary substances.

Abstract: Novel photopolymerizable recording materials suitable in particular for producing photoresist layers and lithographic printing plates are composed of one or more photopolymerizable, olefinically unsaturated organic compounds, optionally a polymeric binder, a photopolymerization initiator, a color-forming system composed of a color former and a photooxidant, novel 4-quinazolone compounds as sensitizers and optionally further additive and/or auxiliary substances.

Abstract: Abstract of the disclosure: Novel photopolymerizable recording materials suitable in particular for producing photoresist layers and lithographic printing plates are composed of one or more photopolymerizable, olefinically unsaturated organic compounds, a photopolymerization initiator, a color-forming system composed of a color former and a photooxidant, novel 4-quinazolone compounds as sensitizers of the formula (I) ##STR1##

Abstract: Photopolymerizable recording materials suitable for producing photoresist layers and lithographic printing plates are composed of one or more photopolymerizable olefinically unsaturated organic compounds, optionally a polymeric binder, one or more photopolymerization initiators, a color-forming system which on irradiation with actinic light causes an increase in the color intensity of the recording material, a sensitizer and optionally further additive and/or auxiliary substances, and contain as the color-forming system(a) one or more colorless or virtually colorless organic compounds which are oxidizable to colored compounds, and(b) a photooxidant for the colorless or virtually colorless organic compound(s) (a),wherein photooxidant (b) comprises an organic salt with a substituted or unsubstituted hetaromatic system, this hetaromatic system having one or more built-in groups of the general formula (I) ##STR1## where R is substituted or unsubstituted alkenyl, alkynyl, hetaryl, alkoxycarbonyl, carbamoyl, alkyls

Abstract: An optical recording material possesses a light-absorbing layer on a base, the said layer containing one or more colorants of the formula (I) ##STR1## where M is two hydrogen atoms or Fe, Cu, Co, Ni, Pb, Cr, Mn, VO, TiO, ZrO, Nb, Ta, Pd, SiCl.sub.2, Sn or SnX.sub.2, X is Cl, Br or I, and A is a divalent radical of an unsaturated, unsubstituted or substituted carbocyclic ring system.The colorants (I) present on the novel recording materials have a high absorption in the range from 650 to 850 nm and accordingly can be written on and read by means of a laser. The colorants can be applied as 20-1000 nm layers on a suitable base by vapor deposition or as a solution or dispersion, with or without the addition of a polymeric binder, by a conventional method.The layers are very stable to atmospheric influences and daylight.