However, the spin-spin relaxation
time, [T.sub.2], determined by the strength of dipolar interaction between neighboring [sup.19]F nuclei and proton nuclei, experiences more significant changes with every increase in concentration of [sup.19]F species.
The relaxation time [T.sub.2] reflects the number of water molecules with spin-spin relaxation
time in the range of proton mobility.
The results of [T.sub.2]-weighted images showed the reduction of the spin-spin relaxation
times ([T.sub.2]) from the lowest to highest concentrations, in which the signal intensity of the [T.sub.2]-weighted images decreased.
The spectra evaluated from echoes 1-10 in comparison with those from echoes 1-21 help to estimate the impact of spin-spin relaxation
on the spectral shapes and intensities.
Table 2 summarises the results from spin-lattice relaxation time [T.sub.1] measurements and spin-spin relaxation
time [T.sub.2]/[T.sub.1[rho]] measurements for [.sup.1.H].
By using NMR spin-spin relaxation
techniques, it has been shown that the melt is not homogeneous in terms of molecular conformations.
The solid echo sequence provided a good approximation to the free induction decay, from which the proton spin-spin relaxation time ([T.sub.2]) was obtained (refs.
[T.sub.2i] : spin-spin relaxation time of each component
The polymer-carbon black interaction was evaluated by the measurements of spin-spin relaxation time in pulsed NMR spectroscopy.
On the other hand, the decline in spin-spin relaxation time beyond the maximum appears to be probably associated with the fact that the ionic mobility is again decreased because of the crystallinity of a low salt concentration PEO phase.
The Fraction of Mobile Lithium Ions and Their Spin-Spin Relaxation Times in (35)NBR-g-PEO/LiC[F.sub.3] S[O.sub.3] ([LiC[F.sub.3] S[O.sub.3]]/[EO] 0.1) Complexes.
The spin-spin relaxations
[T.sub.2] were measured using the