I think I am of the dissenting opinion on this issue.
Ray and touch spells are not weapons per se.
A ray is a spell effect which creates a beam that is typically delivered as a ranged touch attack.
A touch spell refers to the range of the spell in question. In this case, melee.
Like weapons, one can take weapon focus feats to improve attack rolls, or critically hit while delivering them. However, they are spells, not weapons. Dragonfire Inspiration specifically affects weapons (you know, the things listed as simple, martial, exotic). Presumably, one could deliver a touch spell via a melee attack roll (rather than a touch attack), and if the attack is successful then dragonfire inspiration would apply in that case. However, I would really not want the party sorcerer going all MMA on the opposition (in most cases).