Experimental investigations of a proposed chromophore correlation model of self healing of Disperse Orange 11 doped in Poly (methyl methacrylate)
Ramini, Shiva Kumar
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We studied photodegradation and recovery of amplified spontaneous emission (ASE) in Disperse Orange 11 dye doped in Poly(methyl methacrylate)(PMMA) as a function of dye concentration and sample temperature. A simple chromophore correlation model is proposed to explain the self healing mechanism. Based on observations that the molecules are photoresistant at high dye concentration and low temperature, we propose that molecules form correlated regions that are resistant to damage and promote self-healing. We have developed a simple model for photodegradation and recovery that depends on three parameters: the intensity-dependent decay rate, the recovery rate, and the free energy advantage for a molecule being in a correlated group, which we call a domain. This model accounts for all observations of ASE and absorption spectroscopy of DO11 dye in PMMA as a function of time, pump intensity, and concentration during decay and recovery with one fixed set of theses three parameters. Furthermore, the theory predicts the behavior as a function of temperature, and is consistent with all experimental observations.