Compositions comprising organopolysiloxane resins consisting of units of the general formula R a R 1 b (OR 2) c SiO (4-a-b-c)/2, where R may be identical or different and represents hydrogen atom or monovalent, SiC-bonded, optionally substituted hydrocarbon radicals which are free from aliphatic carbon-carbon multiple bonds, R 1 may be identical or different and denotes monovalent, SiC-bonded, optionally substituted hydrocarbon radicals which have aliphatic carbon-carbon multiple bonds, R 2 may be identical or different and denotes hydrogen atom or monovalent, optionally substituted hydrocarbon radicals, a is 0, 1, 2 or 3, b is 0 or 1 and c is 0, 1, 2 or 3, with the proviso that in formula the sum a+b+c<3, in at least one unit of the formula b=1, in at least 50% of the units of the formula a+b=1 and also in at most 10% of the units of the formula a+b=3, based in each case on all siloxane units of the formula in organopolysiloxane resin, organic compounds having at least one unit of the formula CR 3 2 =CR 3 -CO-Z-, where R 3 may be identical or different and denotes hydrogen atom, cyano radical -CN or a monovalent, optionally substituted hydrocarbon radical which may be interrupted by heteroatoms, Z may be identical or different and denotes -O- or -NR 5 - and R 5 may be identical or different and denotes hydrogen atom or a monovalent, optionally substituted hydrocarbon radical which may be interrupted by heteroatoms, initiators, and fillers. organopolysiloxane resins consisting of units of the general formula R a R 1 b (OR 2) c SiO (4-a-b-c)/2, where R may be identical or different and represents hydrogen atom or monovalent, SiC-bonded, optionally substituted hydrocarbon radicals which are free from aliphatic carbon-carbon multiple bonds, R 1 may be identical or different and denotes monovalent, SiC-bonded, optionally substituted hydrocarbon radicals which have aliphatic carbon-carbon multiple bonds, R 2 may be identical or different and denotes hydrogen atom or monovalent, optionally substituted hydrocarbon radicals, a is 0, 1, 2 or 3, b is 0 or 1 and c is 0, 1, 2 or 3, with the proviso that in formula the sum a+b+c<3, in at least one unit of the formula b=1, in at least 50% of the units of the formula a+b=1 and also in at most 10% of the units of the formula a+b=3, based in each case on all siloxane units of the formula in organopolysiloxane resin, R may be identical or different and represents hydrogen atom or monovalent, SiC-bonded, optionally substituted hydrocarbon radicals which are free from aliphatic carbon-carbon multiple bonds, R 1 may be identical or different and denotes monovalent, SiC-bonded, optionally substituted hydrocarbon radicals which have aliphatic carbon-carbon multiple bonds, R 2 may be identical or different and denotes hydrogen atom or monovalent, optionally substituted hydrocarbon radicals, a is 0, 1, 2 or 3, b is 0 or 1 and c is 0, 1, 2 or 3, with the proviso that in formula the sum a+b+c<3, in at least one unit of the formula b=1, in at least 50% of the units of the formula a+b=1 and also in at most 10% of the units of the formula a+b=3, based in each case on all siloxane units of the formula in organopolysiloxane resin, organic compounds having at least one unit of the formula CR 3 2 =CR 3 -CO-Z-, where R 3 may be identical or different and denotes hydrogen atom, cyano radical -CN or a monovalent, optionally substituted hydrocarbon radical which may be interrupted by heteroatoms, Z may be identical or different and denotes -O- or -NR 5 - and R 5 may be identical or different and denotes hydrogen atom or a monovalent, optionally substituted hydrocarbon radical which may be interrupted by heteroatoms, R 3 may be identical or different and denotes hydrogen atom, cyano radical -CN or a monovalent, optionally substituted hydrocarbon radical which may be interrupted by heteroatoms, Z may be identical or different and denotes -O- or -NR 5 - and R 5 may be identical or different and denotes hydrogen atom or a monovalent, optionally substituted hydrocarbon radical which may be interrupted by heteroatoms, initiators, and fillers.