Universal character of relaxation of the intensity of light scattering by boron oxide melt in the temperature range 300–340°C

Resumo

It has been established that the process of stabilization of the boron oxide melt in the temperature range 300–340°С is accompanied by universal changes in the intensity of the polarized V_v component of light scattering characterized with the formation of a minimum. It has been demonstrated that the above feature does not depend on the direction of the intensity approaching to the stationary state for the selected temperature; i.e., it is observed in the process of intensity relaxation from both high and low temperatures. Upon attainment of the minimal values, the increase of the V_v intensity with the stabilization time was found to be satisfactorily described by the empirical dependence of the exponential type. The characteristic times of intensity changes calculated in accordance with the respective equation significantly exceed the times of structural relaxation and increase along with the temperature decrease in accordance with the exponential dependence. It has been established that the characteristic times of intensity changes as its values approach the stationary one from a higher temperature are larger than when approaching from a lower temperature. It has been shown that under these conditions, changes in the intensity of the depolarized H_v component are characterized with the formation of a maximum registered for both modes (sample cooling and heating). It has been revealed that the increase of the H_v intensity in the maximum does not exceed 10% of its regular value, which allows relating the formation of a minimum of the V_v component to the decrease of the isotropic light scattering intensity.