Thermal imaging members and methods

Abstract

There are described thermal imaging members and thermal imaging methods utilizing unsymmetrical rhodamine compounds. The rhodamine color-forming compounds exhibit a first color when in a crystalline form and a second color, different from the first color, when in an amorphous form.

1 . A thermal imaging member comprising a substrate carrying an image-forming layer comprising a compound represented by the formula 
       
         
           
           
               
               
           
         
       
       wherein:
 R 1 , R 4 , R 5 , R 6 , R 7 , and R 8  are each independently selected from the group consisting of hydrogen, alkyl, substituted alkyl, alkenyl, substituted alkenyl, heterocycloalkyl, substituted heterocycloalkyl alkoxy, substituted alkoxy, substituted carbonyl, acylamino, halogen, aryl, substituted aryl, heteroaryl and substituted heteroaryl; 
 R 2  is a 2-alkylphenyl group; 
 R 3  is hydrogen; 
 R 9  is absent or selected from the group consisting of hydrogen, alkyl, substituted alkyl, alkenyl, substituted alkenyl, heterocycloalkyl, substituted heterocycloalkyl, alkoxy, substituted alkoxy, substituted carbonyl, halogen, aryl, substituted aryl, heteroaryl, substituted heteroaryl, amino, substituted amino, alkylamino, substituted alkylamino, arylamino and substituted arylamino; 
 R 10 , R 11  and R 12  are each independently selected from the group consisting of hydrogen, alkyl, substituted alkyl, alkenyl, substituted alkenyl, heterocycloalkyl, substituted heterocycloalkyl, alkoxy, substituted alkoxy, substituted carbonyl, halogen, aryl, substituted aryl, heteroaryl, substituted heteroaryl, amino, substituted amino, alkylamino, substituted alkylamino, arylamino and substituted arylamino; 
 R 13  is selected from the group consisting of alkyl, substituted alkyl, alkenyl, substituted alkenyl, heterocycloalkyl and substituted heterocycloalkyl; 
 R 14  is selected from the group consisting of alkyl, substituted alkyl, alkenyl, substituted alkenyl, heterocycloalkyl and substituted heterocycloalkyl; 
 R 15 , R 16 , R 17  and R 18  are each independently selected from the group consisting of hydrogen, alkyl, substituted alkyl, alkenyl, substituted alkenyl, heterocycloalkyl, substituted heterocycloalkyl, alkoxy, substituted alkoxy, substituted carbonyl, halogen, aryl, substituted aryl, heteroaryl, substituted heteroaryl, amino, substituted amino, alkylamino, substituted alkylamino, arylamino and substituted arylamino; and 
 X 1  is carbon or nitrogen; 
 
       wherein said compound is colorless in the crystalline form and magenta colored in the amorphous form. 
     
     
         2 - 8 . (canceled)