The fluorescence technique was employed to study thermal phase transitions of iota (-) carrageenan (IC) in CaCl2 solution. IC gels underwent coil to double helix (c-h) and double helix to dimer (h-d) transitions upon cooling. Upon heating IC gels presented dimer to double helix (d-h) and double helix to coil (h-c) transitions showing hysteresis types of transition paths. Scattered light Isc and fluorescence intensity I were monitored against temperature to determine phase transitions. Transition ...