| abstract |
An indicating device for indicating the time and temperature history of an object. The indicating device includes a reservoir containing an indicating material that liquefies at or above a predetermined temperature mounted on a base sheet, a removable barrier impervious to the indicating material interposed between the reservoir and a wick, wherein the wick is placed in contact with the reservoir after the barrier is removed to enable the migration of the indicating material along the wick at a controlled rate. The wick is constructed of generally hydrophobic materials so that the migration rate of the indicating materials along the wick is generally independent of changes in the ambient humidity. |