engleski

Piezochromism, kinetics and mechanism of solid-state phase transition of aminoazobenzene salts

This work represents a solid-state kinetics and mechanism studies of the high pressure induced phase transition of 4-azobenzeneammonium sulphates (piezochromic effect). At room temperature the compound is a stable orange colored polycrystalline material, but in KBr pellet under the high mechanical pressure it changes color to violet. The kinetics of this conversion was analyzed by measuring the IR spectral changes at different temperatures and by using the Avrami - Erofeev methodology. From the analysis of the typical sigmoid kinetic curves, we speculate about possible mechanisms. From these kinetic studies it also follows that the transition state obtained after the pressure impact affords "non-Arrhenius behavior" because it changes its structure with variations in temperature. The mechanistic interpretation is also based on the single crystal X-ray structure determination

piezochromism ; aminoazobenzene salts ; solid state reactions

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