Repetitively pulsed laser calorimetry has been developed and applied to measure the intensity dependent absorption of NaCl, KCl and KBr at 10.6 μm. The absorption increases as much as 70% at high laser intensity. Furthermore, multipulse damage data was obtained for KBr which indicates that the absorption increases very rapidly at intensities just below the single pulse damage threshold. The functional form of this phenomenon is still not well characterized. A simple model is suggested and the course of necessary additional investigations is discussed in this paper.