Testing mode-coupling predictions for α and β relaxation in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Ca</mml:mi></mml:mrow><mml:mrow><mml:mn>0.4</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">K</mml:mi></mml:mrow><mml:mrow><mml:mn>0.6</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>(<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">NO</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mo>)</mml:mo></mml:mrow><mml:mrow><mml:mn>1.4</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>near the liquid-glass transition by light scattering

Abstract

Light-scattering studies of the liquid-glass transition of ${\mathrm{Ca}}_{0.4}$${\mathrm{K}}_{0.6}$(${\mathrm{NO}}_{3}$${)}_{1.4}$ have been carried out from 305 to 23\ifmmode^\circ\else\textdegree\fi{}C. Composite spectra covering over four decades in frequency were obtained by combining data obtained with a Sandercock tandem Fabry-P\'erot interferometer and Raman spectra. Two-step relaxation processes were observed in the supercooled liquid near the glass transition. The \ensuremath{\alpha} relaxation exhibits a temperature-independent stretching for T&gt;${\mathit{T}}_{\mathit{c}}$ with ${\mathit{T}}_{\mathit{c}}$\ensuremath{\approxeq}105 \ifmmode^\circ\else\textdegree\fi{}C, which is about 45\ifmmode^\circ\else\textdegree\fi{}C above the glass transition temperature. The \ensuremath{\beta}-relaxation frequency scale indicates critical slowing down when the temperature approaches ${\mathit{T}}_{\mathit{c}}$ from either above or below. Scaling analyses for both \ensuremath{\alpha} and \ensuremath{\beta} relaxations provide good agreement with the predictions of mode-coupling theory.