Effect of temperature of the triboluminescence of tartrate crystals

Abstract

The triboluminescence (TL) intensity in tartaric acid, sodium tartrate, dipotassium tartrate, and ammonium tartrate crystals has been measured in the temperature range of 27-120°C. It has been found that the triboluminescence intensity in the tartrate crystals decreases with temperature and follows the relation ${I_s}^{T_1}-{I_s}^{T_2}=I_0(T_2-T_1)\exp \left[\right(\frac{E_a}{k}\left)\right(\frac{1}{T_1}-\frac{1}{T_2}\left)\right]$. The TL intensity at a fixed temperature of the crystals is higher when that temperature is attained by heating the crystals than by cooling them from a higher temperature. It has been discussed that the decrease in the saturation value of triboluminescence intensity of the tartrate crystals with temperature is (i) due to decrease of their Young's modulus of elasticity and (ii) due to increase in the probability of diffusion of the excited triboluminescent centers with radiationless transition.