The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 15, 1994
Filed:
Aug. 20, 1991
Applicant:
Inventors:
Marcis M Kampe, Brookline, MA (US);
David P Waller, Lexington, MA (US);
David C Whritenour, Franklin, MA (US);
Assignee:
Polaroid Corporation, Cambridge, MA (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G02F / ; C07D / ; C07D / ; C07D / ;
U.S. Cl.
CPC ...
252583 ; 549 41 ; 549 51 ; 549 52 ; 549265 ;
Abstract
Disclosed is a class of bridged phthalides and sulfinate esters which exhibit reversible thermochromism. At room temperature and in the presence of base, these compounds are substantially colorless but upon the application of heat they become colored, reverting to their original colorless or weakly colored state upon cooling. This colorless to colored, temperature-dependent cycle can be repeated many times. These compounds have utility as temperature sensors and as thermal pH indicators.