Initial stage of the development of an optothermochemical instability in solid transparent insulators

An analysis is made of the formation of an absorbing inhomogeneity in solid transparent insulators under the action of high-power optical radiation. The inhomogeneity appears because of a thermally activated chemical reaction and the analysis is carried out during the stage when the inhomogeneity is optically thin. A relationship is established between localization of the process and the degree of nonlinearity of the temperature dependence of the chemical reaction rate. A quasisteady thermal regime is considered when the delocalizing action of heat conduction is manifested most strongly.