Job titles are just words. They don't necessarily mean anything and when they do, they likely mean two different things between two different companies or even two different projects.
Having said that, I'd wager that a "solution architect" role would tend more towards the overall solution while the "technical architect" role would tend more towards a specific part of the overall solution.
I've only run across the TA job title with a vendor. There it was a senior developer who thoroughly knew the guts of the system AND could be trusted with high level design and architecture decisions. In other words, a nearly impossible assignment on a product developed over many years by dozens of people all over the world and customized nearly beyond recognition by the customer (us).
A good question is never answered. It is not a bolt to be tightened into place but a seed to be planted and to bear more seed toward the hope of greening the landscape of the idea. John Ciardi
The only times I've come accross those job titles, a "TA" was more junior than an "SA".
A Solution Architect looks after things from a higher level, possibly overseeing a programme of projects rather than just the one. They could also be involved in a lot more than simply software development, for example hardware, 3rd party software, business process re-engineering and anything that makes up the overall "solution" that a customer has purchased.
A Technical Architect has a lower-level focus, and typically deals with the Software (and possibly hardware) issues on one project (or product line).
Having said that "Architect" is probably one of the vaugest job titles in the Industry and in practice means very little.
Solution Architect has higher responsibility, more experienced, good domain knowledge, responsible for more than one projects. His main reponsibility would be to streamline different techologies used in different projects, foucs on reducing costs and finding a better/cheap solution. His mantra would be to reduce costs and improve revenue for the account he is responsible for.
He is assisted by few Business stakeholders, Techincal architects etc
---Just my thoughts
You can't wake a person who is <b><i>pretending</i></b> to be asleep.<br />Like what <b>"it"</b> does not like - <i> Gurdjieff </i>