Temperature-dependent absorption spectrum of betaine-30 in methanol

Motional narrowing of broadband absorption of solvatochromic indicator Betaine 30

“…Following Reichardt, the transition energies E T (30), expressed in kcal/mol units, are widely utilized for characterization of ''polarity'' of various environments [1]. Substantial color change has also been noticed on temperature rise above the ambient [2][3][4][5]. On cooling down to glass temperature the solvatothermochromism is even stronger ($10, 1 kcal/mol, 1 kcal/mol ¼ 350 ¼ 350 cm À1 ), and nearly independent of the nature of liquid [6][7][8].…”

The thermochromism of the ET(30) betaine in a micro-heterogeneous medium: A spectral and dynamics simulation study

“…3 also shows that the environments sensed by the dye at the pre-micellar and micellar stages are essentially the same for different poloxamers, in spite of different temperatures of micelle formation and polymer concentrations. Thus, the thermochromic behavior of the E T (30) betaine in these systems during the micellization process is similar to its behavior in methanol at variable temperature [4].…”

“…A different behavior had been observed in solvents like ethanol and acetonitrile [3,4], where a small, but perceptible shift of the solvatochromic band of 1 was recorded with the rising temperature. This situation was also observed in our systems, after the polymeric micelle had been formed.…”

“…The thermochromism of the E T (30) betaine has been investigated in pure solvents [2][3][4], and in binary solvent mixtures [5][6][7][8]. In pure solvents, two different situations have emerged from the spectral variations of the probe with the temperature.…”

“…In pure solvents, two different situations have emerged from the spectral variations of the probe with the temperature. In one case, in solutions of methanol [4], the observation of an isosbestic point was interpreted as arising from two differently solvated forms of the betaine in equilibrium. A second behavior was observed in solvents like ethanol [4] and acetonitrile [3], where a small, but perceptible shift of the solvatochromic band of 1 was recorded with the rising temperature.…”