A composition comprising: an ethylene/alpha-olefin/diene interpolymer; a peroxide comprising at least one -O-O- peroxide bond; a bis-TEMPO compound having the Structure I wherein R 1, R 2, R 3 and R 4 are each independently selected from the group consisting of H and C 1 -C 6 alkyl groups; X is selected from the group consisting of S, O, N, P, Se, a carbonyl group (C=O), a carboxyl group (O-C=O), an amide group (N-C=O), an azo group (N=N), an imino group (C=N), a carbamate group (N-C=O), a peroxy group (O-O), a phosphono group (- 2 P=O), a phosphate group (O=P- 3), a sulfonyl group ((O=) 2 S), a sulfinyl group (O=S), a sulfonate ester group ((O=) 2 S-O), a sulfonate ester group (O=S-O), and combinations thereof; Y is selected from the group consisting of a substituted or unsubstituted aliphatic alkyl group, a substituted or unsubstituted aromatic alkyl group, a heterocyclic group, a siloxane group, an ethylene glycol group, an imide group, and combinations thereof; and n is greater than 1, and wherein the ratio of the molar amount of nitroxide (NO') groups of component to the molar amount of the peroxide bonds of component is from 0.100:1.000 to 1.000:1.000. an ethylene/alpha-olefin/diene interpolymer; a peroxide comprising at least one -O-O- peroxide bond; a bis-TEMPO compound having the Structure I wherein R 1, R 2, R 3 and R 4 are each independently selected from the group consisting of H and C 1 -C 6 alkyl groups; X is selected from the group consisting of S, O, N, P, Se, a carbonyl group (C=O), a carboxyl group (O-C=O), an amide group (N-C=O), an azo group (N=N), an imino group (C=N), a carbamate group (N-C=O), a peroxy group (O-O), a phosphono group (- 2 P=O), a phosphate group (O=P- 3), a sulfonyl group ((O=) 2 S), a sulfinyl group (O=S), a sulfonate ester group ((O=) 2 S-O), a sulfonate ester group (O=S-O), and combinations thereof; Y is selected from the group consisting of a substituted or unsubstituted aliphatic alkyl group, a substituted or unsubstituted aromatic alkyl group, a heterocyclic group, a siloxane group, an ethylene glycol group, an imide group, and combinations thereof; and n is greater than 1, and wherein the ratio of the molar amount of nitroxide (NO') groups of component to the molar amount of the peroxide bonds of component is from 0.100:1.000 to 1.000:1.000. wherein R 1, R 2, R 3 and R 4 are each independently selected from the group consisting of H and C 1 -C 6 alkyl groups; X is selected from the group consisting of S, O, N, P, Se, a carbonyl group (C=O), a carboxyl group (O-C=O), an amide group (N-C=O), an azo group (N=N), an imino group (C=N), a carbamate group (N-C=O), a peroxy group (O-O), a phosphono group (- 2 P=O), a phosphate group (O=P- 3), a sulfonyl group ((O=) 2 S), a sulfinyl group (O=S), a sulfonate ester group ((O=) 2 S-O), a sulfonate ester group (O=S-O), and combinations thereof; Y is selected from the group consisting of a substituted or unsubstituted aliphatic alkyl group, a substituted or unsubstituted aromatic alkyl group, a heterocyclic group, a siloxane group, an ethylene glycol group, an imide group, and combinations thereof; and n is greater than 1, and wherein the ratio of the molar amount of nitroxide (NO') groups of component to the molar amount of the peroxide bonds of component is from 0.100:1.000 to 1.000:1.000.