Prolonged irradiation with light causes a variety of chemical and structural modi fications in wool fibers. This study investigates the time dependence of such modifi cations using determinations of the relative native α-helix content (HX r) and wet bundle tensile strength (Rw). For all conditions, HXr decreases with time following on the In-time scale curves of very similar shapes, which can be superimposed onto a common mastercurve relating to a first-order denaturation process. A strong pro tagonistic effect of humidity is detected. The time-dependence of tensile strength shows a pronounced qualitative similarity to the HXr- results. Data set interrelation is well described by linear regression with and without a y-axis intercept. The significance of this observation with respect to the structure of the intermediate filaments is discussed.
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