The present invention provides a time indicator and method of use for
determining and visually displaying the passage of a predetermined period
of time. The time indicator of the present invention comprises a top
portion and a bottom portion. The top portion is a multi-layer segment
comprising a dye support layer coated with a masking layer, which
containing a viewing window therethrough, and a non-curing ink or dye
permeable polymer layer containing a migrating agent. The bottom portion
is a multi-layer segment comprising a base support layer and a migrating
ink or dye printed on the top surface of the base segment. The time
indicator apparatus further comprises a removable impervious film or
middle layer, which can be removed allowing the top and bottom portions
to come into contact with one another, thereby activating the time
indicator. The time indicator of the present invention allows one to
follow the uniform directional visual dye migration through the viewing
window.