Unlike for data files, SQL Server does not use multiple files for the transaction log in any way that improves performance. The writes are not striped across files. Instead SQL Server will write to one file, then the next, then the next, wrapping to the first file when all the VLFs are full, just as it would with one file. In other words, it moves sequentially through the files for new transactions.

I haven’t found a BOL reference for this, and don’t really feel like continuing the search, but Kim Tripp blogs about it here and it’s mentioned in the log file internals MCM video.