Infrared absorbing cyanine dyes for dye-donor element used in laser-induced thermal dye transfer

In a process of forming a laser-induced thermal dye transfer image comprising

• (a) imagewise-heating by means of a laser a dye-donor element comprising a support having thereon a dye layer comprising a polymeric binder and an infrared-absorbing material which is different from the dye in said dye layer, and
• (b) transferring a dye image to a dye-receiving element to form said laser-induced thermal dye transfer image,
• the improvement wherein said infrared-absorbing material is a cyanine dye having a solution absorption maximum in methanol of between about 700 nm and 900 nm and having the following formula:
• ##STR10## wherein:
• R.sup.1 and R.sup.2 each independently represents a substituted or unsubstituted alkyl group;
• R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7, and R.sup.8 each independently represents hydrogen or a substituted or unsubstituted alkyl group;
• or any two of said R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7 or R.sup.8 groups may be joined together, directly or through one or more methyne or methylene groups to complete a substituted or unsubstituted carbocyclic or heterocyclic ring of 5 to 9 members;
• Z.sup.1 and Z.sup.2 each independently represents hydrogen or the atoms necessary to complete a unsubstituted or substituted benzene or naphthalene ring;
• Y.sup.1 represents a dialkyl-substituted carbon atom, a vinylene group, an oxygen atom, a sulphur atom, a selenium atom, a nitrogen atom with an R.sup.1 or a substituted or unsubstituted aryl group attached, or a direct bond between the .beta.-ring vinylene carbon and the carbon at the R.sup.4 position;
• Y.sup.2 represents a dialkyl-substituted carbon atom, a vinylene group, an oxygen atom, a sulphur atom, a selenium atom, a nitrogen atom with an R.sup.1 or a substituted or unsubstituted aryl group attached, or a direct bond between the .beta.-ring vinylene carbon and the carbon at the R.sup.7 position;
• J represents hydrogen;
• a substituted or unsubstituted alkyl group;
• a substituted or unsubstituted aryl group;
• a halogen atom;
• or a nitrogen atom substituted with an alkyl or aryl group, or the atoms necessary to complete a 5- or 6-membered heterocyclic ring;
• n and m each independently represents 0, 1 or 2;
• and
• X is a monovalent anion.

In a thermal dye transfer assemblage comprising:

• (a) a dye-donor element comprising a support having a dye layer comprising a polymeric binder and an infrared absorbing material which is different from the dye in said dye layer, and
• (b) a dye-receiving element comprising a support having thereon a dye image-receiving layer,
• said dye-receiving element being in a superposed relationship with said dye-donor element so that said dye layer is adjacent to said dye image-receiving layer,
• the improvement wherein said infrared-absorbing material is a cyanine dye having a solution absorption maximum in methanol of between about 700 nm and 900 nm and having the following formula:
• ##STR11## wherein:
• R.sup.1 and R.sup.2 each independently represents a substituted or unsubstituted alkyl group;
• R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7, and R.sup.8 each independently represents hydrogen or a substituted or unsubstituted alkyl group;
• or any two of said R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7 or R.sup.8 groups may be joined together, directly or through one or more methyne or methylene groups to complete a substituted or unsubstituted carbocyclic or heterocyclic ring of 5 to 9 members;
• Z.sup.1 and Z.sup.2 each independently represents hydrogen or the atoms necessary to complete a unsubstituted or substituted benzene or naphthalene ring;
• Y.sup.1 represents a dialkyl-substituted carbon atom, a vinylene group, an oxygen atom, a sulphur atom, a selenium atom, a nitrogen atom with an R.sup.1 or a substituted or unsubstituted aryl group attached, or a direct bond between the .beta.-ring vinylene carbon and the carbon at the R.sup.4 position;
• Y.sup.2 represents a dialkyl-substituted carbon atom, a vinylene group, an oxygen atom, a sulphur atom, a selenium atom, a nitrogen atom with an R.sup.1 or a substituted or unsubstituted aryl group attached, or a direct bond between the .beta.-ring vinylene carbon and the carbon at the R.sup.7 position;
• J represents hydrogen;
• a substituted or unsubstituted alkyl group;
• a substituted or unsubstituted aryl group;
• a halogen atom;
• or a nitrogen atom substituted with an alkyl or aryl group, or the atoms necessary to complete a 5- or 6-membered heterocyclic ring;
• n and m each independently represents 0, 1 or 2;
• and
• X is a monovalent anion.