Thermally development imaging materials having backside stabilizers

A photothermographic film pack or stack comprising a plurality of photothermographic materials,

• each photothermographic material comprising a support having on a frontside thereof, one or more thermally-developable imaging layers comprising a binder and in reactive association, a photosensitive silver halide, a non-photosensitive source of reducible silver ions, and a reducing composition for said non-photosensitive source reducible silver ions,
• and on a non-photosensitive backside of said support, a backside layer comprising a binder and an amine organic base as a backside stabilizer, the conjugate acid of said organic base having a pKa greater than 5 and being present in an amount of at least 0.01 mmol/m2,
• wherein said backside stabilizer is represented by the following Structure I:
• wherein R1, R2, and R3 are independently chosen from hydrogen, —C(R4)═NR5, —C(NR6R7)═NR5, substituted or unsubstituted alkyl groups having 1 to 18 carbon atoms, substituted or unsubstituted cycloalkyl groups, substituted or unsubstituted alkenyl groups having 2 to 18 carbon atoms, substituted or unsubstituted carbocyclic aryl groups having 6 or 10 carbon atoms in the aromatic rings, substituted or unsubstituted heterocyclic groups having 5 to 10 carbon, nitrogen, sulfur, and oxygen atoms, and R4, R5, R6, and R7 are independently chosen from the same groups as R1, R2, and R3, or any one or more of R1, R2, R3, R4, R5, R6, and R7 as defined above may be joined with each other and/or the central nitrogen atom to complete one or more substituted or unsubstituted heterocyclic ring(s).