Temperature recorder comprising a liquid crystalline material

A temp. recorder comprises a sensing cell which comprises a reactant mixt. The reactant mixt. comprises a liq. cryst. material, a reactive monomer, and an initiator configured to initiate crosslinking of the reactive monomer and thereby form a sensing material which provides a record of the temp. of the sensing cell when crosslinking occurs. The sensing material comprises a crosslinked network dispersed within the liq. cryst. material, the crosslinked network being formed from the reactive monomer. The sensing cell addnl. comprises first and second elec. conductive electrodes having a spaced relation there between and being connectable to an elec. property measuring device arranged to measure an elec. property of the sensing material.