  We consider experimental data on the dynamics of water (1) in glass-forming
aqueous mixtures with glass transition temperature Tg approaching the putative
Tg=136 K of water from above and below, (2) in confined spaces of nanometer in
size and (3) in the bulk at temperatures above the homogeneous nucleation
temperature. Altogether, the considered relaxation times from the data range
nearly over 15 decades from 10-12 to 103 s. Assisted by the various features in
the isothermal spectra and theoretical interpretation, these considerations
enable us to conclude that relaxation of un-crystallized water is highly
non-cooperative. The exponent Beta_K of its Kohlrausch stretched exponential
correlation function is not far from having the value of one, and hence the
deviation from exponential time decay is slight. Albeit the temperature
dependence of its alpha-relaxation time being non-Arrhenius, the corresponding
Tg-scaled temperature dependence has small steepness index m, likely less than
44 at Tg, and hence water is not 'fragile' as a glassformer. The separation in
time scale of the alpha- and the beta-relaxations is small at Tg, becomes
smaller at higher temperatures, and they merge together shortly above Tg. From
all these properties and by inference, water is highly non-cooperative as a
glass-former, it has short cooperative length-scale, and possibly minimal
configurational entropy and small change of heat capacity at Tg compared with
other organic glass-formers. This conclusion is perhaps unsurprising because
water is the smallest molecule. Our deductions from the data rule out that the
Tg of water is higher than 160 K, and suggest that it is close to the
traditional value of 136 K.
