mapfile -t arr <<< "$string"
while read -r line; do
done <<< "$string"
By default, the read builtin allows \ to escape characters. To turn off this behavior, use the -r option. It is not often you will find a case where you do not want to use -r.
In order to do this in one-line (like you were attempting with read -a), actually requires mapfile in bash v4 or higher: