Origin of Light Scattering

FIGURE 12-14 Schematic diagram of light as an oscillating electric field. 

Note that the oscillations of the dipole occur at the same frequency as the oscillations of the electric field of die light. 

46 It is usual to use the symbol c for the speed of light, but because we are using that symbol to describe concentration, we will use c here. 

FIGURE 12-15 Schematic diagram of light impinging on a spherical molecule and inducing oscillatory motions of the electrons. 

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Lyberis A, Patriarche G, Gredin P, Vivien D, Mortier M (2011) Origin of light scattering in ytterbium doped calcium fluoride transparent ceramic for high power lasers. J Eur Ceram Soc 31 1619-1630... 

Possible Origins of Light Scattering in the Polymer/LC Composite System... 

Before we will start to discuss the origin of light scattering of the polymer/LC (40/60) composite system, we will show a typical example of reversible turbid and transparent changes of the PMMA/E-44 (40/60) composite film corresponding to (a) off- and (b) on-... 

Figure 5. Possible origins of light scattering in the composite film (1) a spatial distortion of nematic directors, (2) a discontinuous change of nematic directors among different LC domains and (3) the mismatch in refractive indices of the components. Also, the turbid and transparent changes are shown under the conditions of off- or on-a.c. electric fields, and mesomorphic- or isotropic- phases.

Equations (10.17) and (10.18) show that both the relative dielectric constant and the refractive index of a substance are measurable properties of matter that quantify the interaction between matter and electric fields of whatever origin. The polarizability is the molecular parameter which is pertinent to this interaction. We shall see in the next section that a also plays an important role in the theory of light scattering. The following example illustrates the use of Eq. (10.17) to evaluate a and considers one aspect of the applicability of this quantity to light scattering. 

In another study [31] it has been reported that haze of LLDPE is mainly a consequence of light scattered by the spherulites. Thus, origin of poor clarity is not the same in LLDPE as in HP LDPE. In HP LDPE the haze is produced by surface defects coming from processing rheology [48,54,55]. Processing variables, therefore, do not have the same effect on LLDPE as they do on HP LDPE. 

Figure 7.6 Intensity of light scattered from an unpolarised beam by a large spherical particle at the origin, as a function of scattering angle 6 (Rayleigh-Gahs-Debye theory). The intensity of light scattered at 135° is less than that at 45°.

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