| 摘要 |
<p>The invention relates to a photochromic gamma butyrolactone having the general formula (I):- <CHEM> in which X represents @@CH2 or @@C(CH3)2; R1, R2 and R4 independently represent a group selected from hydrogen, alkyl or aryl (including substituted aryl), with the proviso that one of R1 and R2 is always hydrogen, and R3 is a 3-thienyl, 3-furyl, 3-benzothienyl or 3-benzofuryl group in which the 2-position is substituted with an alkyl, aralkyl or aryl group (including substituted aryl). The lactones are useful in photolithography and in the production of security inks and markings and in the production of data recording materials.</p> |
