High P-T Raman measurements of solid and fluid hydrogen to above 1100 K at 70 GPa and to above 650 K in 150 GPa range, conditions previously inaccessible by static compression experiments, provide new insight into the behavior of the material under extreme conditions. The data give a direct measure of the melting curve that extends previous optical investigations by up to a factor of 4 in pressure. The magnitude of the vibron frequency temperature derivative d=dT P increases by a factor of 30

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... er the measured pressure range, indicating an increase in intrinsic anharmonicity and weakening of the molecular bond.