Correlation Between Thermal and Mechanical Relaxation in Chalcogenide Glass Fibers

Abstract

International audienceEnthalpy relaxation processes in chalcogenide fibers at room temperature are investigated by differential scanning calorimetry and compared with bending-stress relaxation measurements obtained by rolling fibers on a mandrel and recording the viscoelastic relaxation parameters. While the kinetics of the two processes is very different, several qualitative correlations are demonstrated between the enthalpy state and the mechanical properties of chalcogenide glass fibers. It is observed that the ability to undergo stress relaxation is dependent upon the fictive temperature of the glass. Stress relaxation in a glass far from thermodynamic equilibrium is contingent upon its ability to undergo enthalpy relaxation and is minimal in glasses that have already relaxed enthalpy or in which relaxation time is overwhelmingly large

Aging in chalcohalide glasses: Origin and consequences

“…According to DSC measurements on asprepared and physically aged samples, T f decreases upon aging. In detail, T f of the as-prepared glass is 660 K, whereas that of the glass aged in Ar for 48 h at 0.95T g is 643 K. The decrease of T f upon aging agrees with previous findings [15,27]. However, this H V -T f relation is contrary to that of most oxide glasses [28,29].…”

“…However, a recent study has shown that the strength degradation occurs faster in air than in vacuum [12], indicating the importance of chemical aging. Furthermore, the structural origin of the physical aging remains unclear [13][14][15][16], and the reaction mechanism during chemical aging has not been well understood [12]. In this Letter, we identify the chemical evolvement during the chemical aging in chalcohalide glasses and find out how both physical and chemical aging affect a mechanical property such as hardness.…”

Impact of Drawing Stress on the Tensile Strength of Oxide Glass Fibers

“…In other words, the larger the anisotropy is, the more unstable is the orientated glass structure, and hence the faster and easier the structure relaxes. In a recent study, 43 the stress relaxation is contingent on the simultaneous enthalpy relaxation in thick chalcogenide glass fibers ( d =400 μm). This implies that there is no decoupling between the stress relaxation and the enthalpy relaxation for relatively thick fibers, i.e., the fibers with a low anisotropy.…”

1.8–13 μm supercontinuum generation by pumping at normal dispersion regime of As–Se–Te glass fiber

“…The difference between the glass crystallization temperature and glass transition temperature of Ge–Te–AgI glasses was only 80°C and thus the crystallization was difficult to control during the extrusion and fiber drawing process. As–Se–Te glass has high nonlinear refractive index, wide MIR transmission range and weak crystallization ability . Therefore, As–Se–Te glass is more suitable than binary As–S compounds for drawing fibers for ultra‐wide band spectral conversion.…”